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This paper focuses on the environment of Ethiopia, a country highly sensitive to droughts severely affecting vegetation. Vegetation monitoring of Ethiopian Highlands requires visualization of environmental parameters to assess droughts negatively influencing agricultural sustainable management of crops. Therefore, this study presented mapping of several climate and environmental variables including Palmer Drought Severity Index (PDSI). The data were visualized and interpreted alongside the topographic data to evaluate the environmental conditions for vegetation. The datasets included WorldClim and GEBCO and Digital Chart of the World (DCW). Research has threefold objectives: i) environmental mapping; ii) technical cartographic scripting; iii) data processing. Following variables were visualized on seven new maps: 1) topography; 2) soil moisture; 3) T °C minimum; 4) T °C maximum; 5) Wind speed; 6) Precipitation; 7) Palmer Drought Severity Index (PDSI). New high-resolution thematic environmental maps are presented and the utility of GMT for mapping multi-source datasets is described. With varying degrees of soil moisture (mean value of 15.0), min T°C (−1.8°C to 24°C), max T°C (14.4°C to 40.2°C) and wind speed (0.1 to 6.1 m/s), the maps demonstrate the variability of the PDSI fields over the country area (from −11.7 to 2.3) induced by the complex sum of these variables and intensified by the topographic effects notable over the Ethiopian Highlands which can be used for vegetation analysis. The paper presents seven new maps and contributes to the environmental studies of Ethiopia.

International audience; This paper explores the geomorphological features of the Ninety East Ridge (NER), Indian Ocean. NER presents especially long and linear topographic structure formed as a result of complex regional geophysical and geologic development. The research is based on high precision bathymetric, geological and gravity data. The submarine geomorphology of NER was digitized as three cross-sectional profiles. The profiles were selected in northern, central and southern segments. The depths were visualized in graphs, compared and statistically analyzed by histograms. The study contributes to the geophysical studies of the Indian Ocean.; В данной статье исследуются пространственные вариации геоморфологии хребта Девяностого градуса, также известного как Восточно-Индийский хребет (ВИХ) в Индийском океане в трех сегментах. ВИХ представляет собой необычайно протяженный линейный батиметрический объект с топографией, отражающей сложные геофизические условия и геологическую эволюцию. Исследование основано на компиляции наборов батиметрических, геологических и гравиметрических данных высокого разрешения. Подводная геоморфология была смоделирована с помощью оцифрованных профилей поперечного сечения. Были выбраны три сегмента по геоморфологическим особенностям ВИХ: 1) северный; 2) центральный; 3) южный. Измеренные глубины были визуализированы в виде графиков, проведен сравнительный анализ статистических гистограмм распределения и повторяемости глубин. Работа вносит вклад в региональные исследования геоморфологии дна Индийского океана.

International audience; Landsat-TM of 2001 covering Iceland (15.5°W-21°W, 64.5°N-67°N) was processed using SAGA GIS for testing distance-based Vegetation Indices (VIs): four approaches of Perpendicular Vegetation Index (PVI) and two approaches of Transformed Soil Adjusted Vegetation Index TSAVI. The PVI of vegetation from the soil background line indicated healthiness as a leaf area index (LAI). The results showed that the reflectance for vegetation has a linear relation with soil background line. Four PVI models and two TSAVI shown coefficients of determination with LAI. The dataset demonstrate variations in the calculated coefficients. The mode in the histograms of the PVI based on four different algorithms show the difference:-7.1,-8.36, 2.78 and 7.0. The dataset for the two approaches of TSAVI: first case ranges in 4.4.-80.6 with a bellshape mode of a histogram (8.09 to 23.29) for the first algorithm and an irregular shape for the second algorithm with several modes starting from 0.11 to 0.2 and decreasing to 0.26. SAGA GIS permits the calculation of PVI and TSAVI by computed NDVI based on the intersection of vegetation and soil background. Masking the NIR and R, a linear regression of grids was performed using an equation embedded in SAGA GIS. The advantages of the distance-based PVI and TSAVI consists in the adjusted position of pixels on the soil brightness line which refines it comparing to the slope-based VIs. The paper demonstrates SAGA GIS application in agricultural studies.

The functionality of Generic Mapping Tools (GMT) to process and visualize geospatial information is crucial to the development of the advanced cartographic method. This paper presents modelling and spatial analysis of the marine geological data using GMT shell scripting. GMT demonstrated effective cartographic solutions for visualization of the georeferenced data. The particular feature of GMT consists in its scripting modular approach that enables to use machine learning to explore reliable georeferenced data. Here, the study applies a sequential shell scripting to devise GMT modules for depicting marine geological data on the Mariana Trench. The data cover bathymetry, geophysics, tectonics and geology. The first method makes use of the 'nearneighbor' GMT module for grid contour modelling using Nearest Neighbor algorithm. This form of modelling classifies the geospatial data based on a similarity. The second method presents surface modelling from the initial XYZ-ASCII dataset by a combination of the 'blockmean' and 'surface' modules. The third method includes the use of the modules 'grdimage', 'psbasemap' and 'grdcontour' for plotting. Compared to GIS methods in which data are processed in a menu, GMT presents the console-based approach which automates cartographic data processing. The results present seven new maps and explanations of scripts.A combination of visual approaches applied using a color fill and various textures to represent data, which is effective in allowing readers to assess geophysical setting. The study demonstrated the effectiveness of GMT in geodata visualization.

International audience; Seismicity in Yemen and the Gulf of Aden in a geological context. The study presents geologic investigation of Yemen and the Gulf of Aden with a special focus on geophysical, seismic, tectonic and topographic mapping performed by the integrated approach of QGIS and GMT scripting. Cartographic visualization is crucial in geologic analysis, data processing and prognosis of mineral resource prospects. The region of Yemen and Gulf of Aden was formed as a result of Arabian and African plates movements and still tectonically active. Besides, the Gulf of Aden contains mineral resources of hydrocarbons which makes this region actual for investigation. The IRIS database on earthquakes was used for visualization of the magnitude of submarine earthquakes in the Gulf of Aden for the period of 2007-2020. The paper presents 6 new thematic maps for the region of Yemen and Gulf of Aden. The research presented an analysis of correlation between the geological, topographic and geophysical settings. Through combined approach of cartographic high-resolution data visualization and geologic analysis, this paper contributed to the regional geological studies of Yemen, Gulf of Aden and the Middle East.

Uganda is traversed by the East African Rift System (EARS), which controls its topography and induces high seismicity in the southwestern and western parts of the country, around the Rwenzori Mountains and Albertine Graben. This paper explores the complexity of the geophysical, topographic and geomorphological settings of Uganda for linking the distribution and magnitude of earthquakes to the controlling factors: geomorphology, topography and geophysics. The methodological workflow for an automated plotting of the topographic, geophysical and seismic data includes the following important codes: 'gmt grdimage ug_relief.nc-Cgeo.cpt-R29/35/-1.5/4.3-JM6.5i-I+a15+ne0.75-t50-Xc-P-K > $ps' for topographic visualisation, 'gmt psxy-R-J quakes_UG.ngdc-Wfaint-i4,3,6,6s0.1-h3-Scc-Csteps.cpt-O-K >> $ps' for mapping earthquakes, 'gmt img2grd grav_27.1.img-R29/35.5/-1.5/4.3-Ggrav_UG.grd-T1-I1-E-S0.1-V' for mapping gravity. The steps of the scripting workflow using 'raster' and 'tmap' libraries of R and a variety of GMT modules includes the following most important codes: 'alt = getData("alt", country = "Uganda", path = tempdir()); slope = terrain(alt, opt = "slope"); aspect = terrain(alt, opt = "aspect"); hill = hillShade(slope, aspect, angle = 40, direction = 270)'. The study uses high-resolution spatial datasets GEBCO, EGM-2008, IRIS, gravity grids and SRTM DEM aimed to undertake thematic mapping of Uganda. Nine new maps have been generated using shell scripts of GMT and R for environmental monitoring. Depth of the earthquakes ranges from 4 to 40 Km with frequency of seismic events near Rwenzori Mountains and Albertine Graben for destructive earthquake is less than about five decades. Earthquake magnitudes varied from 3.7 Richter Magnitude Scale (Lake Edward region) to 6.2 Richter local magnitude Makerere scale (M L) (Lake Albert region). Lake Kivu region has earthquakes with magnitudes between 3.8-5.3. The region of Lake Albert had the highest magnitudes and frequency of seismic events, compared to Lakes Kivu and Edward. Earthquakes around the Lake Albert reached the highest magnitude at 6.2 M L. Earthquakes around Lake Victoria reach the maximal level of earthquake magnitude at 5.0 M l , near Lake George-5.3 M L. Earthquakes were mostly recorded in the Albertine Graben of EARS in the Albert, Edward and George lakes and occasionally in Lake Victoria.

International audience; The paper presents the use of scripting cartographic techniques for the visualization of topographic and geomorphological maps by R and GMT. The thematic maps intend to analyze the region of Peru with specific focus on its geomorphology: slope, aspect, elevation and hillshade performed in R libraries ‘raster’ and ‘tmap’. The integrated free materials include several datasets embedded in R library ‘OpenStreetMap’: Stamen, ESRI World Imagery, Bing Maps, National Park Service. The research shows a particular example of the use of open source datasets and free tools available for distance-based online education and research, which becomes an actual tendency in modern geographic research.; El artículo presenta el uso de técnicas cartográficas de scripting para la visualización de mapas topográficos y geomorfológicos por R y GMT. Los mapas temáticos pretenden analizar la región del Perú con un enfoque específico en su geomorfología: pendiente, aspecto, elevación y sombreado realizado en las bibliotecas R «raster» y «tmap». Los materiales integrados incluyen varios conjuntos de datos integrados en la biblioteca R "OpenStreetMap": Stamen, ESRI World Imagery, Bing Maps, National Park Service. La investigación muestra un ejemplo particular del uso de conjuntos de datos de código abierto y herramientas gratuitas disponibles para la educación e investigación en línea a distancia, que se convierte en una tendencia real en la investigación geográfica moderna.

International audience; This study evaluates the geomorphometric parameters of the topography in Ethiopia using scripting cartographic methods by applying R languages (packages 'tmap' and 'raster') and Generic Mapping Tools (GMT) for 2D and 3D topographic modelling. Data were collected from the open source repositories on geospatial data with high resolution: GEBCO with 15 arc-second and ETOPO1 with 1 arc-minute resolution and embedded dataset of SRTM 90 m in 'raster' library of R. The study demonstrated application of the programming approaches in cartographic data visualization and mapping for geomorphometric analysis. This included modelling of slope steepness, aspect and hillshade visualized using DEM SRTM90 to derive geomorphometric parameters of slope, aspect and hillshade of Ethiopia and demonstrate contrasting topography and variability climate setting of Ethiopia. The topography of the country is mapped, including Great Rift Valley, Afar Depression, Ogaden Desert and the most distinctive features of the Ethiopian Highlands. A variety of topographical zones is demonstrated on the presented maps. The results include 6 new maps made using programming console-based approach which is a novel method of cartographic visualization compared to traditional GIS software. The most important fragments of the codes are presented and technical explanations are provided. The presented series of 6 new maps contributes to the cartographic data on Ethiopia and presents the methodology of scripting mapping techniques.

International audience; The South Sandwich Trench located eastward of the Drake Passage in the Scotia Sea between Antarctica and South America is one of the least studied deep-sea trenches. Its geomorphological formation and present shape formed under the strong influence of the tectonic plate movements and various aspects of the geological setting, i.e., sediment thickness, faults, fracture zones and geologic lineaments. The aim of this paper is to link the geological and geophysical setting of the Scotia Sea with individual geomorphological features of the South Sandwich Trench in the context of the phenomena of its formation and evolution. Linking several datasets (GEBCO, ETOPO1, EGM96, GlobSed and marine freeair gravity raster grids, geological vector layers) highlights correlations between various factors affecting deep-sea trench formation and development, using the Generic Mapping Tools (GMT) for cartographic mapping. The paper contributes to the regional studies of the submarine geomorphology in the Antarctic region with a technical application of the GMT cartographic scripting toolset.

International audience; المستخلصتم في هذه الدراسة اعداد خرائط ثنائية الأبعاد وثلاثية الأبعاد لحوض مابين النهرين في العراق والمناطق المجاورة من. خلال تكامل لبيانات متعددة المصادر بواسطة لغة برمجة TMG و R و STGQ. اعتمد رسم الخرائط الجيومورفولوجية والجيولوجية على مجموعات البيانات التي تحتوي على طبقات نقطية ومتجهة للبيانات الجيولوجية والجيوفيزيائية والطوبوغرافية والصخرية والجيوديسية التي تم جمعها من مستودعات مفتوحة المصدر. تتضمن النتائج 8 خرائط جديدة. تقدم هذه الدراسة طريقة رسم خرائط متكاملة تجمع بين أدوات مختلفة لتصور البيانات: STGQ لرسم الخرائط الجيولوجية، TMG لتخطيط الجيود، شذوذ الجاذبية، التصور ثلاثي الأبعاد ورسم الخرائط الطبوغرافية ثنائية الأبعاد، ولغة البرمجة R لنمذجة التضاريس الجيومورفولوجية لأراضي العراق. بينت الخريطة الطوبوغرافية تباين في الإرتفاع من -69 متر تحت مستوى سطح البحر في الخليج العربي الى 3754 متر فوق مستوى سطح البحر في الأجزاء الشمالية الشرقية من العراق. أظهرت الخريطة الجيولوجية ان ترسبات العصر الرباعي (Q) وترسبات العصر الثلاثي (T) هي الترسبات السائدة والتي تقسم العراق بشكل تقريبي الى جزئين (شمالي شرقي وجنوبي غربي). ترسبات العصر الرباعي (Q) هي الترسبات الغالبة التي تغطي حوض مابين النهرين. قدم النموذج ثلاثي الأبعاد رسم منظوري لحوضمابين النهرين وجبال زاكروس.عند تدوير زاوية السمت بمقدار °30/°165. تزداد تموجات الجيود بالإتجاه الشمالي الشرقي: القيمة السالبة الأكثرانخفاضاً للجيود هي (-17 م) وكانت على امتداد الخليج العربي، وتعكس استمرارية الحد الأدنى للجغرافي الهندية. الحد الاعلى للجيود هو 19 في الاتجاه الجنوبي الغربي والشمالي الشرقي. يتباين ارتفاع الجيود في حوض ما بين النهرين من -15 م الى 5 م متوافقتاً مع المنخفض الطوبوغرافي. نموذج جاذبية الهواء الحر أظهر توافق بين قيم الجاذبية والتضاريس والتي تثبت الإتجاه العام لتناقص الكتلة التي تكون سبب لقيم الجاذبية المنخفضة أو السالبة. تختلف قيم انحرافات الجاذبية لـ Faye بين الحد الادنى -124.945 ملي كال الى الحد الأعلى 327.724 ملي كال. من الواضح ان قيمالجاذبية في حوض مابين النهرين هي قيم سالبة.تساهم مخرجات رسم هذه الخرائط (8 خرائط جديدة) في زيادة المعرفة حول الجيومورفولوجيا والجيولوجيا والشذوذ الجيوفيزيائي في العراق مع التركيز على حوض - ما بين النهرين في العراق. تتعلق دراسة أسئلة البحث الفني بتنسيق البيانات الخرائطية ومعالجتها وتكاملها ونمذجتها بواسطة مجموعات بيانات إنشائية متعددة المصادر تغطي العراق. تساهمالورقة بالإضافة الى اعداد الخرائط في الدراسات التكاملية الإقليمية للعراق والشرق الأوسط وحوض مابين النهرين.; The study presents the 2D and 3D mapping of the Mesopotamia Foredeep Basin, Iraq, and the adjacent areas using integrated cartographic approach of multi-source data visualization by Generic Mapping Tools (GMT), R language and QGIS. The geomorphological and geological mapping is based on multiple datasets containing raster and vector layers of the geological, geophysical, topographic, lithological and geodetic data captured from the open source repositories and resulted in 8 new maps. This study develops and presents an integrated cartographic method combining the use of various tools for different tasks in data visualization: QGIS for geological mapping, GMT for mapping geoid, gravity anomalies, 3D mesh visualization and 2D topographic mapping, R language (libraries 'raster' and 'tmap') for modelling relief (slope and aspect) of Iraq. The topography shows variation in data from minimum at-69 m below sea level in the Arabian Gulf, to maximum at 3754 m asl in the NE of Iraq. The map of geologic units of Iraq shows dominating types are Quaternary (Q) and Tertiary (T) that roughly divide the country into two segments (SW and NE). The Mesopotamia Foredeep Basin is dominated by Quaternary (Q). The 3D model of the Iraqi relief presented perspective view of the Mesopotamia Foredeep Basin and Zagros Mts with azimuth rotation at 165°/30°. The geoid undulations increase in NW direction: the lowest, negative values of geoid (-17 m) are over the Arabian Gulf which reflects the continuum of the Indian geopotential minimum. Maximal values of geoid reach 19 m in the SW and NW. The Mesopotamia Foredeep Basin has geoid variations ranging from-15 to 5 m showing correlation with topographic depressions. Free-air gravity model shows correlation of the values with topography proving general trend of the deficit of landmasses causing the negative or lower values in gravity. The values of Faye's gravity anomalies differ from minimum at-124.945 mGal to maximum at 327.724 mGal. The Mesopotamia Foredeep Basin has clearly negative values. The generated cartographic outputs (8 new maps) contribute to the increase of knowledge on the geomorphology, geology and distribution of geophysical anomalies of Iraq with a special focus on Mesopotamia Foredeep Basin. The technical research questions covered by this study relate to the cartographic data formatting, processing, integration and modelling using thematic multi-source datasets covering Iraq. The paper contributes both to the cartographic aspect of integrated mapping and to the regional studies of Iraq, Middle East and the Mesopotamia Foredeep Basin.

International audience; GRASS GIS Modules for Topographic and Geophysical Analysis of the ETOPO1 DEM and Raster Data: North Fiji Basin, Pacific Ocean The paper presents topographic analysis based on the raster data (NetCDF and grid formats) and visualization of the geophysical datasets that resembles the topographic surface. Geographically, the research focuses on the region of North Fiji Basin, South Pacific Ocean. North Fiji Basin is one of the marginal basins located at the converging boundary between the Pacific and Australian tectonic plates and is notable for complex geological settings. Methodology is based on GRASS GIS and includes scripting and cartographic visualization. Data include ETOPO1, GEBCO, EGM96 gravity and geoid raster grids imported to GRASS GIS via GDAL library ('r.in.gdal' module) from NetCDF and GRD formats, evaluated and visualized. Several GRASS modules were used as a sequential scripting for displaying and modelling data. Geomorphometric analysis (slopes, curvature, aspect, elevation) was performed by module 'r.slope.aspect' based on ETOPO1 grid. Statistical data analysis (histograms, polar diagram) for topographic and geoid gravitational fields were visualized by combination of GRASS modules d.rast, g.region, d.polar, d.histogram, d.grid, d.legend, d.text. Topographic analysis reveal that free-air gravity anomaly mark the continental shelf-slope border showing that generally, geophysical settings are dominated by the topographic effect. These observations are consistent with the inferred prominent role of the geophysical settings. The histograms reveal that topography (trenches, abyssal plains, shelf areas) has values between-5,000 and-1,000 m, and a clear peak with major values between 100 and 350 m above sea level. This distribution indicates that dominating depths of the ocean floor in North Fiji Basin are between-1,500 to-3,000 m. The aspect map of the ETOPO1 initial raw raster grid show that the surface has mostly 50°-110° oriented slope followed by data range in 250°-300° oriented slopes which is well correlating with submarine topography and general relief forms. The steepening of the gravity values between 50 and 55 mGal and 58 to 63 mGal indicates geoid undulations suggesting that bathymetry is controlled by the geological settings in the study area. Consolebased scripts of GRASS GIS are presented together with cartographic outputs showing its effectiveness for the geographic spatial analysis.

International audience; The article reports the issues corresponding to the climate variability and possibility of droughts in spatially distinct regions of Paraguay, the Chaco and the Oriental (Paraná Basin). Based on the GMT scripting approach and high-resolution datasets from the TerraClimate and GEBCO, the study examined the extent of the annual climate and environmental variables over Paraguay in 2020: extreme temperatures, wind speed, precipitation, soil moisture, evapotranspiration, Palmer's Drought Severity Index (PDSI), vapour pressure deficit (VPD) and the topography of the country. The environmental and climate parameters demonstrated spatial variability in the Dry Chaco with notable differences in Gran Chaco and Chaco Boreal, wetlands of Pantanal, and tropical rainforests in east of the Paraguay. Besides climate analysis, technical snippets from the GMT scripts regarding the mapping techniques and data processing were explained and commented. Research results show that actual evapotranspiration reaches maximal values in the Paraná Basin (180 mm/yr), and has peaks along the Pilcomayo river (140-150 mm/yr) which well coincides with the soil moisture; the PDSI values are maximal in Chaco Boreal and Gran Chaco; the temperatures are the highest in the N and NW regions of Paraguay; the highest VPD (over 2.0) corresponds to the Chaco Boreal.; O artigo relata as questões correspondentes à variabilidade climática e possibilidade de secas em regiões espacialmente distintas do Paraguai, Chaco e Oriental (Bacia do Paraná). Com base na abordagem de script GMT e conjuntos de dados de alta resolução do TerraClimate e GEBCO, o estudo examinou a extensão do clima anual e variáveis ambientais no Paraguai em 2020: temperaturas extremas, velocidade do vento, precipitação, umidade do solo, evapotranspiração, Severidade da Seca de Palmer Índice (PDSI), déficit de pressão de vapor (VPD) e a topografia do país. Os parâmetros ambientais e climáticos demonstraram variabilidade espacial no Chaco Seco com diferenças notáveis no Gran Chaco e no Chaco Boreal, áreas úmidas do Pantanal e florestas tropicais no leste do Paraguai. Além da análise do clima, fragmentos técnicos dos scripts GMT sobre as técnicas de mapeamento e processamento de dados foram explicados e comentados. Os resultados da pesquisa mostram que a evapotranspiração real atinge valores máximos na Bacia do Paraná (180 mm / ano), e tem picos ao longo do rio Pilcomayo (140-150 mm / ano) que coincide bem com a umidade do solo; os valores PDSI são máximos em Chaco Boreal e Gran Chaco; as temperaturas são mais altas nas regiões N e NW do Paraguai; o VPD mais alto (acima de 2,0) corresponde ao Chaco Boreal

International audience; Edge bundling techniques provide a visual simplification of cluttered \ graph drawings or trail sets. While many bundling techniques exist, \ only few recent ones can handle large datasets and also allow selective \ bundling based on edge attributes. We present a new technique \ that improves on both above points, in terms of increasing both the \ scalability and computational speed of bundling, while keeping the \ quality of the results on par with state-of-the-art techniques. For \ this, we shift the bundling process from the image space to the spectral \ (frequency) space, thereby increasing computational speed. We \ address scalability by proposing a data streaming process that allows \ bundling of extremely large datasets with limited GPU memory. \ We demonstrate our technique on several real-world datasets \ and by comparing it with state-of-the-art bundling methods.

International audience; Multiclass maps are scatterplots, multidimensional projections, or thematic geographic maps where data points have a categorical attribute in addition to two quantitative attributes. This categorical attribute is often rendered using shape or color, which does not scale when overplotting occurs. When the number of data points increases, multiclass maps must resort to data aggregation to remain readable. We present multiclass density maps: multiple 2D histograms computed for each of the category values. Multiclass density maps are meant as a building block to improve the expressiveness and scalability of multiclass map visualization. In this article, we first present a short survey of aggregated multiclass maps, mainly from cartography. We then introduce a declarative model—a simple yet expressive JSON grammar associated with visual semantics—that specifies a wide design space of visualizations for multiclass density maps. Our declarative model is expressive and can be efficiently implemented in visualization front-ends such as modern web browsers. Furthermore, it can be reconfigured dynamically to support data exploration tasks without recomputing the raw data. Finally, we demonstrate how our model can be used to reproduce examples from the past and support exploring data at scale.

International audience; 3D scanners provide a virtual representation of object surfaces at some given precision that depends on many factors such as the object material, the quality of the laser-ray or the resolution of the camera. This precision may even vary over the surface, depending for example on the distance to the scanner which results in uneven and unstructured point sets, with an uncertainty on the coordinates. To enhance the quality of the scanner output, one usually resorts to local surface interpolation between measured points. However, object surfaces often exhibit interesting statistical features such as repetitive geometric textures. Building on this property, we propose a new approach for surface super-resolution that detects repetitive patterns or self-similarities and exploits them to improve the scan resolution by aggregating scattered measures. In contrast with other surface super-resolution methods, our algorithm has two important advantages. First, when handling multiple scans, it does not rely on surface registration. Second, it is able to produce super-resolution from even a single scan. These features are made possible by a new local shape description able to capture differential properties of order above 2. By comparing those descriptors, similarities are detected and used to generate a high-resolution surface. Our results show a clear resolution gain over state-of-the-art interpolation methods.

The research performs urban ecosystem analysis supported by ENVI GIS by integrated studies on land cover types and geospatial modeling of Taipei city. The paper deals with the role of anthropogenic pressure on the structure of the landscape and change of land cover types. Methods included assessment of the impact from anthropogenic activities on the natural ecosystems, evaluation of the rate and scale of landscape dynamics using remote sensing data and GIS. The research aims to assist environmentalists and city planners to evaluate strategies for specific objectives of urban development in Taiwan, China., Comment: 5 pages, 2 figures, 1 table

International audience; The study area is located in Central Europe and focusing on Mecsek Hills, a low mountain range in the south western part of Hungary. The region of central Europe includes complex mis of elements from mediterranean and continental climate, since the area is located in transitional zone of sub-atlantic and sub-mediterranean climate types. Mecsek Hills is a unique region of the Hungarian environment. Its central European location specifies distribution of diverse landscape types, formed under conditions of transitional climatic settings, mixed from sub-atlantic to sub-mediterranean. The distribution of ecosystems in the region illustrate adaptation of soil properties to actual climate conditions. As determined by the present-day climatic and geomorphological settings, soils in the Mecsek region are rich in nutrients, and landscapes are characterized by various mixed soil types. Brown forest soils predominate on hilltops of Mecsek, while alluvial soils on floodplains. According to the underlying soil types, the landscapes are characterized by mixed vegetation types. The most typical is Pannonian mixed forests of temperate broadleaf and mixed forests, common in Euro-Siberian region. There are also forests of Turkey and hornbeam oak in the catchment area of Mecsek region. The dominating vegetation coverage types on the slopes of Mecsek Hills include beech forests, ravine forests and oaks. Some regions of the Mecsek Hills include unique biogeographic areas with endemic species, not founded elsewhere in Carpathian Basin. The overall climate change, especially the global temperature increase, controls balance of heat and water budget on the Hungarian landscapes, and has considerable impact on the agricultural landscapes. In the past decades there were changes in climate, detected in the Carpathian Basin region, which illustrate general fluctuations in the climatic settings in Hungary and change of overall average air temperatures. Combination of the satellite images with GIS techniques is a key method for land patterns identification and classification of ecosystems. Research methodology is based on the GIS spatial analysis tools and classification of Landsat TM image, which was used for visualizing landscapes. An ILWIS GIS was applied to perform spatial analysis and mapping. The research algorithm is clustering, which classifies pixels with similar value of Digital Numbers (DNs) to thematic classes. As a result, spatial analysis on distribution of land cover patterns was performed. Data processing include image pre-processing, enhancement, classification, spatial analysis and interpretation. A land cover map was created by classifying study area into land categories. The core method used in the current work for the interpretation of imagery is clustering algorithm. This method is based on the remote sensing general principle that each unique pixel on a multichannel image has spectral signature defined by the reflectance of its DN in each spectral band. The DNs of pixels create unique signatures for various objects, distinguishable from other objects. Multispectral cluster classification was applied for the Landsat TM image, by extracting information about values of the pixels DNs, analyzing their spectral signatures.Current work demonstrated analysis of climate factors affecting ecological settings of Mecsek Hulls, and local landscapes visualized by means of ILWIS GIS and remote sensing data (Landsat TM). The results consist in recognized distribution of land use patterns. ILWIS GIS is a convenient open source GIS, useful for spatial analysis and land use monitoring. Clustering method is useful for ecological mapping, since it enables objective identification of the land types in regions characterized by high land heterogeneity and complex structure, such as agricultural fields mixed with natural land cover types. The experience of Landsat TM imagery processing by means of ILWIS GIS, described in the current work, is a contribution towards agricultural mapping.

Presented at the CzechGlobe PGS Conference. 2014 Feb 06. Oral presentation. Czech Republic, Brno, 2014. Research area: Taipei urban landscapes, Taiwan R.O.C. Research aim: spatio-temporal analysis of urban dynamics in study area during 15 years (1990-2005) Research objective: application of geoinformatic tools, remote sensing data and application of methodology to spatial analysis for urban studies, a case study of Taipei Current work has been supported by the Taiwan Ministry of Education Short Term Research Award (STRA) for research stay at National Taiwan University (NTU), Department of Geography during April-May 2013. The research was performed using ENVI GIS software using Landsat TM images for years 1990 and 2005. The landscapes in study area at both Landsat TM images were classified using "K-means" algorithm into different land use types The area covered by each land cover class is compared and dynamics is analyzed for respecting years. The changes in selected land cover types were analyzed and the human impacts on natural landscapes detected. Finally, classified land cover types across study area were compared at both maps of land cover types for the years 1990 and 2005, respectively.

International audience; The emphasis of this research is application of spatial analysis using clustering algorithm, and remote sensing data (Landsat TM imagery) for agricultural mapping of land cover types. The study area covers Mecsek Hills region, located in south-western Hungary. This region is characterized by high land heterogeneity and complex landscape structure, caused by intense agricultural land use in the region with mixed vegetation type and high environmental value. The research data consists in Landsat TM scenes taken for years for years 1992, 1999 and 2006. The methodology is based on cluster classification algorithm available in ILWIS GIS. Based on clustering technique, the agricultural land cover classes were identified by association of pixels on the Landsat TM scenes to thematic clusters. Different land use types were classified, which include natural vegetation coverage, anthropogenic areas and agricultural fields, sub-divided to various crop types. Once classification was complete, agricultural thematic maps have been created. The final research output consists in three independent agricultural thematic maps of land cover types for years 1992, 1999 and 2006.

International audience

Данная работа представляет результат геопространственного анализа выбранной территории (западная часть Турции, регион Измир) с комбинированным использованием космических снимков Google Earth, Landsat TM и ГИС ПО Erdas Imagine. В работе рассмотрены преимущества совместного использования космических снимков разной категории и детальности (мультиспектральные снимки Landsat TM и ETM+, а также Google Earth веб-сервис) вкупе с ГИС обеспечением для задач геопространственного анализа, часто решаемые в Высшей школе на курсах географии и наук о Земле. Данная работа приводит пример успешного изучения ландшафтов. Изучение распространения различных типов земной поверхности, моделированное с помощью Landsat TM и Google Earth позволяет анализировать динамику изменений ландшафтов, а также подтверждает возможность эффективного использования веб-сервиса Google Earth для тематического картографирования. Для классификации снимков были использованы технологии обработки снимков методами доступных модулей ПО Erdas Imagine. Веб-сервис Google Earth был успешно использован для верификации и валидации результатов картографирования с помощью модуля «Linking with Google Earth».

© 2018 The Author(s) Computer Graphics Forum © 2018 The Eurographics Association and John Wiley & Sons Ltd. Published by John Wiley & Sons Ltd. Street-level imagery is now abundant but does not have sufficient capture density to be usable for Image-Based Rendering (IBR) of facades. We present a method that exploits repetitive elements in facades - such as windows - to perform data augmentation, in turn improving camera calibration, reconstructed geometry and overall rendering quality for IBR. The main intuition behind our approach is that a few views of several instances of an element provide similar information to many views of a single instance of that element. We first select similar instances of an element from 3–4 views of a facade and transform them into a common coordinate system, creating a “platonic” element. We use this common space to refine the camera calibration of each view of each instance and to reconstruct a 3D mesh of the element with multi-view stereo, that we regularize to obtain a piecewise-planar mesh aligned with dominant image contours. Observing the same element under multiple views also allows us to identify reflective areas - such as glass panels - which we use at rendering time to generate plausible reflections using an environment map. Our detailed 3D mesh, augmented set of views, and reflection mask enable image-based rendering of much higher quality than results obtained using the input images directly.

International audience; The plenoptic function, also known as the light field or the lumigraph, contains the information about the radiance of all optical rays that go through all points in space in a scene. Since no camera can capture all this information, one of the main challenges in plenoptic imaging is light field reconstruction, which consists in interpolating the ray samples captured by the cameras to create a dense light field. Most existing methods perform this task by first attempting some kind of 3D reconstruction of the visible scene. Our method, in contrast, works by modeling the scene as a set of visual points, which describe how each point moves in the image when a camera moves. We compute visual point models of various degrees of complexity, and show that high-dimensional models are able to replicate complex optical effects such as reflection or refraction, and a model selection method can differentiate quasi-Lambertian from non-Lambertian areas in the scene.

International audience; We study camera models to generate stereoscopic zoom shots, i.e. using very long focal length lenses. Stereoscopic images are usually generated with two cameras. However, we show that two cameras are unable to create compelling stereoscopic images for extreme focal length lenses. Inspired by the practitioners' use of the long focal length lenses we propose two different configurations: we " get closer " to the scene, or we create " perspective deformations ". Both configurations are build upon state-of-the-art image-based rendering methods allowing the formal deduction of precise parameters of the cameras depending on the scene to be acquired. We present a proof of concept with the acquisition of a representative simplified scene. We discuss the advantages and drawbacks of each configuration.

International audience; We study camera models to generate stereoscopic zoom shots, i.e. using very long focal length lenses. Stereoscopic images are usually generated with two cameras. However, we show that two cameras are unable to create compelling stereoscopic images for extreme focal length lenses. Inspired by the practitioners' use of the long focal length lenses we propose two different configurations: we " get closer " to the scene, or we create " perspective deformations ". Both configurations are build upon state-of-the-art image-based rendering methods allowing the formal deduction of precise parameters of the cameras depending on the scene to be acquired. We present a proof of concept with the acquisition of a representative simplified scene. We discuss the advantages and drawbacks of each configuration.

International audience; We present a novel approach to facilitate the creation of stylized 2D rigid body animations. Our approach can handle multiple rigid objects following complex physically-simulated trajectories with collisions, while retaining a unique artistic style directly specified by the user. Starting with an existing target animation (e.g., produced by a physical simulation engine) an artist interactively draws over a sparse set of frames, and the desired appearance and motion stylization is automatically propagated to the rest of the sequence. The stylization process may also be performed in an off-line batch process from a small set of drawn sequences. To achieve these goals, we combine parametric deformation synthesis that generalizes and reuses hand-drawn exemplars, with non-parametric techniques that enhance the hand-drawn appearance of the synthesized sequence. We demonstrate the potential of our method on various complex rigid body animations which are created with an expressive hand-drawn look using notably less manual interventions as compared to traditional techniques.

This article introduces a method for accurately computing the visible contours of a smooth 3D surface for stylization. This is a surprisingly difficult problem, and previous methods are prone to topological errors, such as gaps in the outline. Our approach is to generate, for each viewpoint, a new triangle mesh with contours that are topologically equivalent and geometrically close to those of the original smooth surface. The contours of the mesh can then be rendered with exact visibility. The core of the approach is Contour Consistency, a way to prove topological equivalence between the contours of two surfaces. Producing a surface tessellation that satisfies this property is itself challenging; to this end, we introduce a type of triangle that ensures consistency at the contour. We then introduce an iterative mesh generation procedure, based on these ideas. This procedure does not fully guarantee consistency, but errors are not noticeable in our experiments. Our algorithm can operate on any smooth input surface representation; we use Catmull-Clark subdivision surfaces in our implementation. We demonstrate results computing contours of complex 3D objects, on which our method eliminates the contour artifacts of other methods.

International audience; We introduce Visual Sedimentation, a novel design metaphor for visualizing data streams directly inspired by the physical process of sedimentation. Visualizing data streams (e. g., Tweets, RSS, Emails) is challenging as incoming data arrive at unpredictable rates and have to remain readable. For data streams, clearly expressing chronological order while avoiding clutter, and keeping aging data visible, are important. The metaphor is drawn from the real-world sedimentation processes: objects fall due to gravity, and aggregate into strata over time. Inspired by this metaphor, data is visually depicted as falling objects using a force model to land on a surface, aggregating into strata over time. In this paper, we discuss how this metaphor addresses the specific challenge of smoothing the transition between incoming and aging data. We describe the metaphor's design space, a toolkit developed to facilitate its implementation, and example applications to a range of case studies. We then explore the generative capabilities of the design space through our toolkit. We finally illustrate creative extensions of the metaphor when applied to real streams of data.

The display of space filling data is still a challenge for the community of visualization. Direct volume rendering (DVR) is one of the most important techniques developed to achieve direct perception of such volumetric data. It is based on semitransparent representations, where the data are accumulated in a depth-dependent order. However, it produces images that may be difficult to understand, and thus several techniques have been proposed so as to improve its effectiveness, using for instance lighting models or simpler representations (e.g., maximum intensity projection). In this article, we present three perceptual studies that examine how DVR meets its goals, in either static or dynamic context. We show that a static representation is highly ambiguous, even in simple cases, but this can be counterbalanced by use of dynamic cues (i.e., motion parallax) provided that the rendering parameters are correctly tuned. In addition, perspective projections are demonstrated to provide relevant information to disambiguate depth perception in dynamic displays.

International audience; Algebraic Point Set Surfaces (APSS) define a surface from a set of points using local moving least-squares (MLS) fitting of algebraic spheres. In this paper we first revisit the spherical fitting problem and provide a new, more generic solution that includes intuitive parameters for curvature control of the fitted spheres. As a second contribution we present a novel real-time rendering system of such surfaces using a dynamic up-sampling strategy combined with a conventional splatting algorithm for high quality rendering. Our approach also includes a new view dependent geometric error tailored to efficient and adaptive up-sampling of the surface. One of the key features of our system is its high degree of flexibility that enables us to achieve high performance even for highly dynamic data or complex models by exploiting temporal coherence at the primitive level. We also address the issue of efficient neighbor queries and discuss several spatial search data structures with respect to construction, access and GPU friendliness. Finally, we present an efficient parallel GPU implementation of the algorithms and search structures.

International audience; Environmental mapping is a necessary tool for the geoscience research in the university classes of geography, GIS cartography and mapping. However, GIS methods of processing remote sensing data are often being discussed, and the optimal approaches are disputed. This work reports innovative approach of the processing Landsat TM satellite image in ILWIS GIS software using unsupervised and supervised classification methods. The methods of ILWIS GIS are compared and the results described in this paper. The methodology is based on the use of supervised classification of the satellite image, an innovative method in geographic research. Supervised classification of the raster imagery aimes at the recognizing of the class membership for each pixel during image analysis. The supervised classification of the multi-spectral imagery has been performed using 'Classify' operator in ILWIS applied to Landsat TM 1988. The classification process included following steps. First, the models of the classes were defined by creating a "sample sat" in ILWIS GIS. Namely, the training pixels with similar spectral values were defined and selected as representations for various classes. These pixels have contrasting colors, visually visible and distinguishable on the image, which serve as training areas for diverse classes. The sample pixels were defined in the Sample Set Editor in ILWIS, which was initially created in the main menu. A created Sample Set has a reference to the set of Landsat bands (1-7), which are needed to create sample statistics. After assigning pixel sets, a raster polygon map was automatically created with .mpr file extension. It contained sample pixels, location and legend, i.e. the names of the classes allocated to pixels. Easy interpretation of the image strongly depends on the optimal color composite map. The classification has been completed in interactive way, using several attempts of creating training samples, selecting various sample sets and respective pixels selected in Sample Set Editor using domain for classification ―Landclasses. The classification was repeated the until the final results were achieved. Shadows of green colors represent grass, shrub vegetation coverage and forest canopy. The results demonstrate successful application of the innovative approach of technical satellite image processing for the studies of the environment. The presented methods can be used by students of geography.

International audience; Current work is aimed at the deriving of information from the remote sensed VHR data using a priori knowledge in the Object Based Image Analysis (OBIA) approach. OBIA technology is new and effective tool for urban mapping, as it enables dealing with raster images for detailed and precise cartography. Specific focus of this study is selected urban areas of the city of Brussels, Belgium. The study is performed using panchromatic very high resolution (VHR) image processed in the eCognition software. The operation “Multi-resolution Segmentation” was chosen for image processing, as this is one of the most important image processing tools. During segmentation the image was divided up into large homogeneous regions and isolated shapes into the separate polygons within the study area. This procedure was performed at a different scale factors to adjust local conditions, such as urban structures, contrast factors, topology, etc. The four first layers in the layers legend represent multispectral image, while the fifth layer belongs to the panchromatic image. These two images were processed, in order to benefit from the high spatial and spectral resolution of the images which have different properties. Besides, processing of both of them gave various results: the panchromatic VHR image enabled to achieve very detailed segmentation of the image. The nearest neighbour classifies subdivide image into objects based on the image sample using mean spectral signature values of the objects. The results are presented by accurate geographic classification of the raster image. The objects are grouped into the separated classes connected with each other according to the hierarchical values of their features. The target objects are detected using existing knowledge which helped to find out what information exists in the objects based on training test areas. The classification is done using nearest neighbour principle after the manual defining of the number of sample objects. The method of the multiresolution segmentation procedure using OBIA approach was applied to the image in eCognition software and the image was processed. The classification is based on the segmentation of the whole image into meaningful polygons, according to the fuzzy logic approach and nearest neighbour classifier which is similar to the supervised classification in usual image analysis software. The work proved effectiveness of the object based image analysis approach for satellite data processing in urban mapping.

International audience; Edge bundling methods reduce visual clutter of dense and occluded graphs. However, existing bundling techniques either ignore edge properties such as direction and data attributes, or are otherwise computationally not scalable, which makes them unsuitable for tasks such as exploration of large trajectory datasets. We present a new framework to generate bundled graph layouts according to any numerical edge attributes such as directions, timestamps or weights. We propose a GPU-based implementation linear in number of edges, which makes our algorithm applicable to large datasets. We demonstrate our method with applications in the analysis of aircraft trajectory datasets and eye-movement traces.

International audience; Successfully predicting visual attention can significantly improve many aspects of computer graphics: scene design, interactivity and rendering. Most previous attention models are mainly based on low-level image features, and fail to take into account highlevel factors such as scene context, topology or task. Low-level saliency has previously been combined with task maps, but only for predetermined tasks. Thus the application of these methods to graphics - e.g. for selective rendering - has not achieved its full potential. In this paper we present the first automated high level saliency predictor incorporating two hypotheses from perception and cognitive science which can be adapted to different tasks. The first states that a scene is comprised of objects expected to be found in a specific context as well objects out of context which are salient (scene schemata) while the other claims that viewer's attention is captured by isolated objects (singletons). We propose a new model of attention by extending Eckstein's Differential Weighting Model. We conducted a formal eye-tracking experiment which confirmed that object saliency guides attention to specific objects in a game scene and determined appropriate parameters for a model. We present a GPU based system architecture that estimates the probabilities of objects to be attended in real-time. We embedded this tool in a game level editor to automatically adjust game level difficulty based on object saliency, offering a novel way to facilitate game design. We perform a study confirming that game level completion time depends on object topology as predicted by our system.

Summarization: Attention-based Level-Of–Detail (LOD) managers downgrade the quality of areas that are expected to go unnoticed by an observer to economize on computational resources. The perceptibility of lowered visual fidelity is determined by the accuracy of the attention model that assigns quality levels. Most previous attention based LOD managers do not take into account saliency provoked by context, failing to provide consistently accurate attention predictions. In this work, we extend a recent high level saliency model with four additional components yielding more accurate predictions: an object-intrinsic factor accounting for canonical form of objects, an object-context factor for contextual isolation of objects, a feature uniqueness term that accounts for the number of salient features in an image, and a temporal context that generates recurring fixations for objects inconsistent with the context. We conduct a perceptual experiment to acquire the weighting factors to initialize our model. We design C-LOD, a LOD manager that maintains a constant frame rate on mobile devices by dynamically re-adjusting material quality on secondary visual features of non-attended objects. In a proof of concept study we establish that by incorporating C-LOD, complex effects such as parallax occlusion mapping usually omitted in mobile devices can now be employed, without overloading GPU capability and, at the same time, conserving battery power. Presented on: Computer Graphics Forum

Presented work illustrates application of the GIS based processing of various geographic data: satellite images and CORINE (Coordination of Information on the Environment) layers at the lessons of geography in the high schools and universities. The research illustrates GIS application for understanding, visualizing and modeling landscapes of the Earth. Practically, the work aims to demonstrate students, how mapping land cover types can be done using GIS and combination of vector and raster geospatial data., P. Lemenkova. "Opportunities for Classes of Geography in the High School: the Use of CORINE Project Data, Satellite Images and IDRISI GIS for Geovisualization". In: Perspectives for the Development of Higher Education. Proceedings of 7th International Conference (Grodno State Agrarian University GGAU, Apr. 24–25, 2014). Ed. by V. Pestis et al. Belarus, Grodno: GGAU Press, 2014, pp. 284–286. isbn: 978-985-537-042-1. doi: 10.6084/m9.figshare.7211933.

International audience; We present an interactive approach for decompositing bitmap drawings and studio photographs into opaque and semi-transparent vector layers. Semi-transparent layers are especially challenging to extract, since they require the inversion of the non-linear compositing equation. We make this problem tractable by exploiting the parametric nature of vector gradients, jointly separating and vectorising semi-transparent regions. Specifically, we constrain the foreground colours to vary according to linear or radial parametric gradients, restricting the number of unknowns and allowing our system to efficiently solve for an editable semi-transparent foreground. We propose a progressive workflow, where the user successively selects a semi-transparent or opaque region in the bitmap, which our algorithm separates as a foreground vector gradient and a background bitmap layer. The user can choose to decompose the background further or vectorise it as an opaque layer. The resulting layered vector representation allows a variety of edits, such as modifying the shape of highlights, adding texture to an object or changing its diffuse colour.

We present a thorough study to evaluate different light field editing interfaces, tools and workflows from a user perspective. This is of special relevance given the multidimensional nature of light fields, which may make common image editing tasks become complex in light field space. We additionally investigate the potential benefits of using depth information when editing, and the limitations imposed by imperfect depth reconstruction using current techniques. We perform two different experiments, collecting both objective and subjective data from a varied number of editing tasks of increasing complexity based on local point-and-click tools. In the first experiment, we rely on perfect depth from synthetic light fields, and focus on simple edits. This allows us to gain basic insight on light field editing, and to design a more advanced editing interface. This is then used in the second experiment, employing real light fields with imperfect reconstructed depth, and covering more advanced editing tasks. Our study shows that users can edit light fields with our tested interface and tools, even in the presence of imperfect depth. They follow different workflows depending on the task at hand, mostly relying on a combination of different depth cues. Last, we confirm our findings by asking a set of artists to freely edit both real and synthetic light fields.

International audience; Some materials, such as coffee, milk or marble, have a soft translucent aspect because of sub-surface scattering: light enters them, is scattered several times inside before leaving in a different place. A full representation of sub-surface scattering effects in illumination simulation is computationally expensive. The main difficult comes from multiple scattering events: the high number of events increases the uncertainty on the result, forcing us to allocate more time for the computations. In this paper, we show that there is a strong correlation between the surface effects of multiple scattering inside the material and the effects after just two scatter events. This knowledge will help in accelerating multiple scattering effects. We exploit this knowledge to provide a model and implementation for fast computation of double-scattering events, using a precomputed density function stored in a compact way.

International audience; Color map textures applied directly to surfaces, to geometric microsurface details, or to procedural functions (such as noise), are commonly used to enhance visual detail. Their simplicity and ability to mimic a wide range of realistic appearances have led to their adoption in many rendering problems. As with any textured or geometric detail, proper filtering is needed to reduce aliasing when viewed across a range of distances, but accurate and efficient color map filtering remains an open problem for several reasons: color maps are complex non-linear functions, especially when mapped through procedural noise and/or geometry-dependent functions, and the effects of perspective and masking further complicate the filtering over a pixel's footprint. We accurately solve this problem by computing and sampling from specialized filtering distributions on-the-fly, yielding very fast performance. We filter color map textures applied to (macro-scale) surfaces, as well as color maps applied according to (micro-scale) geometric details. We introduce a novel representation of a (potentially modulated) color map's distribution over pixel footprints using Gaussian statistics and, in the more complex case of high-resolution color mapped microsurface details, our filtering is view- and light-dependent, and capable of correctly handling masking and occlusion effects. Our results match ground truth and our solution is well suited to real-time applications, requires only a few lines of shader code (provided in supplemental material), is high performance, and has a negligible memory footprint.

International audience; The transformation of video clips into stylized animations remains an active research topic in Computer Graphics. A key challenge is to reproduce the look of traditional artistic styles whilst minimizing distracting flickering and sliding artifacts; i.e. with temporal coherence. This chapter surveys the spectrum of available video stylization techniques, focusing on algorithms encouraging the temporally coherent placement of rendering marks, and discusses the trade-offs necessary to achieve coherence. We begin with flow-based adaptations of stroke based rendering (SBR) and texture advection capable of painting video. We then chart the development of the field, and its fusion with Computer Vision, to deliver coherent mid-level scene representations. These representations enable the rotoscoping of rendering marks on to temporally coherent video regions, enhancing the diversity and temporal coherence of stylization. In discussing coherence, we formalize the problem of temporal coherence in terms of three defined criteria, and compare and contrast video stylization using these.

Best Paper HPG 2012; International audience; Sparse Voxel Octrees (SVOs) represent efficiently complex geometry on current GPUs. Despite the fact that LoDs come naturally with octrees, interpolating and filtering SVOs are still issues in current approaches. In this paper, we propose a representation for the appearance of a detailed surface with associated attributes stored within a voxel octree. We store macro- and micro-descriptors of the surface shape and associated attributes in each voxel. We represent the surface macroscopically with a signed distance field and we encode subvoxel microdetails with Gaussian descriptors of the surface and attributes within the voxel. Our voxels form a continuous field interpolated through space and scales, through which we cast conic rays. Within the ray marching steps, we compute the occlusion distribution produced by the macro-surface inside a pixel footprint, we use the microdescriptors to reconstruct light- and view-dependent shading, and we combine fragments in an A-buffer way. Our representation efficiently accounts for various subpixel effects. It can be continuously interpolated and filtered, it is scalable, and it allows for efficient depth-of-field.We illustrate the quality of these various effects by displaying surfaces at different scales, and we show that the timings per pixel are scale-independent.

Automated film editing involves the generation of the position, orientation, motion and selection of virtual cameras in interactive 3D graphics applications. There is a pressing demand for techniques to assist and automate the control of virtual cameras in the computer games industry where the rapid development of personal computers and high performance consoles has led to substantial improvements in the visual fidelity of games. The goal of this survey is to characterize the spectrum of applications that require automated film editing, present a summary of state-of-the-art models and techniques, and identify both promising avenues and hot topics for future research., Dans le contexte du jeu vidéo, le montage automatique consiste à placer et cadrer les caméras virtuelles au cours du jeu en suivant les règles cinématographiques classiques. Cet état de l'art présente les applications, modèles et techniques de montage automatique, en soulignant les directions de recherche les plus prometteuses et les plus nouvelles.

Generating content for third person games and machinima requires knowledge in cinematography (camera placement, framing, lighting) and editing (cutting between cameras). In existing systems, such knowledge either comes from the final user (machinima) or from a database of precompiled solutions (third person games). In this paper, we present a system that can make decisions about editing and automatically generate a grammatically correct movie during game interaction. While previous work described techniques for choosing camera setups and generating virtual footage, most of them do not propose general computational frameworks to express variations in directorial styles. We introduce a framework for generating a well-edited movie from such footage, based on film grammar. Our system computes a sequence of shots by simultaneously choosing which camera to use, when to cut in and out of the shot, and which camera to cut to. We cast film editing as a cost minimization problem in the space of possible shot sequences and provide an efficient search algorithm for computing the edit with minimal latency. In contrast to previous work, our method precisely examines all possible edit points and relies on a well-founded model to account for shot duration., La création de contenus pour le jeu vidéo et le machinima necessite des connaissances en cinématographie et montage. Nous présentons un système capable de calculer automatiquement le cadrage et le montage des caméras virtuelles de facon a produire un film d'animation au cours du jeu, sans intervention des joueurs. Pour cela, nous formalisons le montage cinématographique comme un problème de minimisation d'énergie et proposons des solutions interactives pour calculer un film de moindre coû, tout en controlant le rythme de montage.

International audience; Non-photorealistic rendering (NPR) algorithms allow the creation of images in a variety of styles, ranging from line drawing and pen-and-ink to oil painting and watercolor. These algorithms provide greater flexibility, control and automation over traditional drawing and painting. Despite significant progress over the past 15 years, the application of NPR to the generation of stylized animations remains an active area of research. The main challenge of computer generated stylized animations is to reproduce the look of traditional drawings and paintings while minimizing distracting flickering and sliding artifacts present in hand-drawn animations. These goals are inherently conflicting and any attempt to address the temporal coherence of stylized animations is a trade-off. This state-of-the-art report is motivated by the growing number of methods proposed in recent years and the need for a comprehensive analysis of the trade-offs they propose. We formalize the problem of temporal coherence in terms of goals and compare existing methods accordingly. We propose an analysis for both line and region stylization methods and discuss initial steps toward their perceptual evaluation. The goal of our report is to help uninformed readers to choose the method that best suits their needs, as well as motivate further research to address the limitations of existing methods.

Generating films from 3D animations requires knowledge in cinematography (camera placement, framing and lighting) and editing (cutting between cameras). In applications where the user is already engaged in other tasks, such as playing a game, directing virtual actors, or narrating a story, it appears desirable to build systems that can make decisions about cinematography and editing and automatically generate a grammatically correct movie according to film grammar. In this paper, we introduce a framework for generating a well-edited movie based on the rules of film editing. Specifically, our system computes a sequence of shots by simultaneously choosing which camera to use, when to cut in and out of the shot, and where to cut to. We cast film editing as a cost minimization problem in the space of possible shot sequences and provide an efficient search algorithm. The method is illustrated with multiple edits of the same footage in different editing rhythms and styles., La génération de films d'animation 3D requiert des connaissances en cinématographie (placement des caméras, cadrage, éclairage) et en montage (choix des plans). Nous proposons un système permettant de proposer automatiquement des choix de cinématographie et de montage au sein d'un logiciel d'animation 3D. Pour cela nous définissons une fonction de cout permettant de pénaliser les principales erreurs de cadrage et de montage, et une méthode d'optimisation en ligne permettant de choisir une solution de moindre cout en focntion de petit nombre de paramètres de style offert aux animateurs.

International audience; Supporting the strong demand in data storage, computation and interactive performances required by visual analytics applications is still a challenge. All currently existing visual analytics applications need to build their own specialised infrastructure for their specific problem. One of the most difficult issues of visual analytics is that it is both user driven and data-driven. It is user-driven because during the interactive steps of the analysis, the user is specifying algorithms and parameters to explore the data. It is also data-driven because new data is made available to the user at unpredictable times, such as when algorithms run or databases are updated. This chapter describes the landscape of software and hardware solutions to address this difficult issues.

International audience; Supporting the strong demand in data storage, computation and interactive performances required by visual analytics applications is still a challenge. All currently existing visual analytics applications need to build their own specialised infrastructure for their specific problem. One of the most difficult issues of visual analytics is that it is both user driven and data-driven. It is user-driven because during the interactive steps of the analysis, the user is specifying algorithms and parameters to explore the data. It is also data-driven because new data is made available to the user at unpredictable times, such as when algorithms run or databases are updated. This chapter describes the landscape of software and hardware solutions to address this difficult issues.

International audience; Supporting the strong demand in data storage, computation and interactive performances required by visual analytics applications is still a challenge. All currently existing visual analytics applications need to build their own specialised infrastructure for their specific problem. One of the most difficult issues of visual analytics is that it is both user driven and data-driven. It is user-driven because during the interactive steps of the analysis, the user is specifying algorithms and parameters to explore the data. It is also data-driven because new data is made available to the user at unpredictable times, such as when algorithms run or databases are updated. This chapter describes the landscape of software and hardware solutions to address this difficult issues.

International audience; Supporting the strong demand in data storage, computation and interactive performances required by visual analytics applications is still a challenge. All currently existing visual analytics applications need to build their own specialised infrastructure for their specific problem. One of the most difficult issues of visual analytics is that it is both user driven and data-driven. It is user-driven because during the interactive steps of the analysis, the user is specifying algorithms and parameters to explore the data. It is also data-driven because new data is made available to the user at unpredictable times, such as when algorithms run or databases are updated. This chapter describes the landscape of software and hardware solutions to address this difficult issues.