74 results on '"map transformation"'
Search Results
2. Proxemic maps for immersive visualization.
- Author
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Ghaemi, Zeinab, Engelke, Ulrich, Ens, Barrett, and Jenny, Bernhard
- Subjects
SHARED virtual environments ,MAPS ,VISUALIZATION ,VIRTUAL reality - Abstract
In human computer interaction, proxemics describes the ways that people use space to interact with other people or objects. We focus on proxemic maps, which are virtual maps in immersive environments that react to proxemic interaction. Proxemic maps take advantage of new opportunities brought about by immersive visualization, where virtual maps can be freely positioned in virtual or physical space and adapt themselves relative to the spatial position of the viewer. We discuss proxemic interactions that alter the content and type of maps, including changing scale, symbolization, type of visualization and geometry. We propose a novel transformation that changes the geometry of maps based on their proximity to users. Users move the map back and forth and the map transitions between ring, horizontal, vertical and cylindrical geometries. The ring geometry surrounds the user and aligns features on the map with features in the real world. We implemented the map transformation in virtual reality and conducted a user study to evaluate it. The results of the user study indicate that participants preferred the ring and horizontal geometries. The ring geometry is useful because it simplifies connecting virtual features on the map with real features in the landscape, while the horizontal geometry provides an overall view of the landscape. We further found that combination of different geometries helped the study participants to overcome the limitations of each geometry. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
3. Improved Feature Map Merging Using Virtual Supporting Lines for Multi-Robot Systems.
- Author
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Lee, Heon-Cheol and Lee, Beom-Hee
- Subjects
ROBOTICS ,SELF-organizing maps ,MEASUREMENT ,ITERATIVE methods (Mathematics) ,LINEAR algebra ,MATRICES (Mathematics) ,STATISTICAL correlation ,DETECTORS - Abstract
This paper addresses the problem of feature map merging, which is one of the essential techniques for multi-robot systems. If inter-robot measurements are not available for feature map merging, the only way to obtain the map transformation matrix is feature map matching. However, the conventional feature map matching technique requires too much computation time because it has to be iteratively performed to compute the degree of the mismatch between multiple feature maps. This paper proposes a non-iterative feature map merging technique using virtual supporting lines (VSLs) which is also accurate and robust. The proposed technique extracts the spectral information of multiple feature maps using VSLs and obtains the map transformation matrix using the circular cross-correlation between the extracted spectral information of the multiple feature maps. The proposed technique was tested on feature maps produced by experiments with vision sensors, which was performed non-iteratively. In addition, it consistently showed a high acceptance index, which indicates the degree of accuracy for feature map merging. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
4. Enhancing adaptive composite map projections: Wagner transformation between the Lambert azimuthal and the transverse cylindrical equal-area projections.
- Author
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Jenny, Bernhard and Šavrič, Bojan
- Subjects
MAP projection ,MAP scales ,PARAMETER estimation ,GEOGRAPHIC information systems ,LINEAR equations - Abstract
The adaptive composite map projection technique changes the projection to minimize distortion for the geographic area shown on a map. This article improves the transition between the Lambert azimuthal projection and the transverse equal-area cylindrical projection that are used by adaptive composite projections for portrait-format maps. Originally, a transverse Albers conic projection was suggested for transforming between these two projections, resulting in graticules that are not symmetric relative to the central meridian. We propose the alternative transverse Wagner transformation between the two projections and provide equations and parameters for the transition. The suggested technique results in a graticule that is symmetric relative to the central meridian, and a map transformation that is visually continuous with changing map scale. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
5. Thermal conductivity changes of photo-elastic semiconductor excited in gravitational field with hydrostatic initial stress and internal heat source.
- Author
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Mahdy, A.M.S., Lotfy, Kh., and El-Bary, A. A.
- Subjects
HYDROSTATIC stress ,THERMAL conductivity ,GRAVITATIONAL fields ,SEMICONDUCTOR materials ,TRANSPORT theory - Abstract
In this work, the effect of hydrostatic initial stress is studied with the exited semiconductor material. Electrons are exited at the free surface of the elastic semiconductor medium using the photo-thermal-elastic theory during the transport (diffusion) process. The thermal memories are due to the dual-phase-lag (DPL) relaxation times of the heat conduction equation with a novel model. In this model, the thermal conductivity is chosen as a linear dependent function of the thermal temperature impact which is variable. The effect of gravitational field is taken into account during the two-dimensional (2D) elastic deformation under the impact of an internal heat source. The Kirchhoff transformation mapping is used. The harmonic wave (normal mode) method is applied for the 2D governing equations to obtain the main physical fields analytically. Some thermal and mechanical forces are applied with other elastic-plasma conditions at the free surface of the semiconductor material to get the complete solutions. Some comparisons used a novel parameters which depend on the DPL model and the differences in the thermal conductivity parameters and they are illustrated graphically and discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
6. Enhanced-spectrum-based map merging for multi-robot systems.
- Author
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Lee, Heon-Cheol and Lee, Beom-Hee
- Subjects
GRIDS (Cartography) ,SPECTRUM analysis ,ROBOT control systems ,T-matrix ,ROBOT dynamics ,INFORMATION theory - Abstract
This paper addresses the problem of grid map merging for multi-robot systems, which can be resolved by acquiring the map transformation matrix (MTM) among robot maps. Without the initial correspondence or any rendezvous among robots, the only way to acquire the MTM is to find and match the common regions of individual robot maps. This paper proposes a novel map merging technique which is capable of merging individual robot maps by matching the spectral information of robot maps. The proposed technique extracts the spectra of robot maps and enhances the extracted spectra using visual landmarks. Then, the MTM is accurately acquired by finding the maximum cross-correlation among the enhanced spectra. Experimental results in outdoor environments show that the proposed technique was performed successfully. Also, the comparison result shows that the map merging errors were significantly reduced by the proposed technique. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
7. Phase synthesis in wave-optical engineering: mapping- and diffuser-type approaches.
- Author
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Senthilkumaran, Paramasivam and Wyrowski, Frank
- Subjects
BEAM optics ,ENGINEERING - Abstract
The synthesis of phase functions to manipulate free propagation characteristics of fields is of fundamental concern in wave-optical engineering. In optical and digital holography, two basic approaches have been proposed: the use of diffuse illumination and the application of map transformation techniques. While the first approach uses a scattering concept, the latter applies geometrical optics arguments. In today's optical engineering, both concepts constitute two extreme cases of the general phase synthesis problem which is typically solved by projection algorithms. Characteristics of diffuser-type and mapping-type approaches in phase synthesis are compared with special emphasis on bandwidth, smoothing and information distribution constraints. As a basic tool, iterative Fourier transform algorithms are developed and applied, which do not stagnate in phase vortexes. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
8. The seer and the seen: Surveying Palantir's surveillance platform.
- Author
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Iliadis, Andrew and Acker, Amelia
- Subjects
CORPORATE history ,DATA integration ,PROPHETS ,METADATA ,GOVERNMENT agencies ,INFORMATION technology - Abstract
Palantir is among the most secretive and understudied surveillance firms globally. The company supplies information technology solutions for data integration and tracking to police and government agencies, humanitarian organizations, and corporations. To illuminate and learn more about Palantir's opaque surveillance practices, we begin by sketching Palantir's company history and contract network, followed by an explanation of key terms associated with Palantir's technology area and a description of the firm's platform ecosystem. We then summarize current scholarship on Palantir's continuing role in policing, intelligence, and security operations. Our primary contribution and analysis are a computational topic modeling of Palantir's surveillance patents (n = 155), including their topics and themes. We end by discussing the concept of infrastructuring to understand Palantir as a surveillance platform, where we theorize information standards like administrative metadata as phenomena for structuring social worlds in and through access to digital information. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
9. Multiscale depthwise separable convolution based network for high-resolution image segmentation.
- Author
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Zhang, Ke, Bello, Inuwa Mamuda, Su, Yu, Wang, Jingyu, and Maryam, Ibrahim
- Subjects
IMAGE segmentation ,DEEP learning ,REMOTE sensing ,PIXELS - Abstract
Deep learning-based segmentation methods have demonstrated significant performance over their traditional counterparts. However, striving for better accuracy with such networks usually leads to the deterioration of the network's computational efficiency, thereby rendering them inefficient for deployment on resource constraint devices. Establishing the required tradeoff between the accuracy of pixel prediction and computational efficiency remains challenging. In this article, a lightweight multiscale segmentation framework is proposed. We leverage the representation power of different receptive fields to attain optimal accuracy while maintaining computational efficiency by embedding the sparse network architecture with the depthwise separable convolution at the multiscale level. Experimental results from two challenging remote sensing segmentation datasets show that the proposed network can achieve substantial pixel prediction accuracy at relatively low computational overhead compared to state-of-the-art networks. [ABSTRACT FROM AUTHOR]
- Published
- 2022
- Full Text
- View/download PDF
10. Mapping the global spatio-temporal dynamics of COVID-19 outbreak using cartograms during the first 150 days of the pandemic.
- Author
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Yalcin, Mustafa
- Subjects
COVID-19 pandemic ,COVID-19 ,GEOGRAPHIC information systems ,PANDEMICS ,SARS-CoV-2 ,WORLD health - Abstract
The novel coronavirus (COVID-19) pandemic is a public health emergency of international concern that caused disaster consequences all over the world. To mitigate and manage the pandemic, geographical information systems (GIS)-based spatial analysis has been used in a key role. To this aim, many GIS-based maps are produced by many national and international institutions. However, the produced maps are prepared by conventional methods and the features in these maps representing by their areal size. This paper proposes the diffusion-based cartograms for visualization of the COVID-19 outbreak. In the study, daily country-level data of the first 150 days of the COVID-19 outbreak were obtained from WHO, and the spread and spatial patterns of the epidemic were presented according to the number of confirmed cases and deaths. As a result of the study, it was observed that the cartogram is a powerful visualization tool and superior to the classical methods. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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- View/download PDF
11. An event-driven manufacturing information system architecture for Industry 4.0.
- Author
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Theorin, Alfred, Bengtsson, Kristofer, Provost, Julien, Lieder, Michael, Johnsson, Charlotta, Lundholm, Thomas, and Lennartson, Bengt
- Subjects
MANUFACTURING processes ,FACTORY management ,DECISION making ,ECONOMIC competition ,MANAGEMENT information systems ,VISUALIZATION - Abstract
Future manufacturing systems need to be more flexible, to embrace tougher and constantly changing market demands. They need to make better use of plant data, ideally utilising all data from the entire plant. Low-level data should be refined to real-time information for decision-making, to facilitate competitiveness through informed and timely decisions. The Line Information System Architecture (LISA), is presented in this paper. It is an event-driven architecture featuring loose coupling, a prototype-oriented information model and formalised transformation services. LISA is designed to enable flexible factory integration and data utilisation. The focus of LISA is on integration of devices and services on all levels, simplifying hardware changes and integration of new smart services as well as supporting continuous improvements on information visualisation and control. The architecture has been evaluated on both real industrial data and industrial demonstrators and it is also being installed at a large automotive company. This article is an extended and revised version of the paper presented at the 2015 IFAC Symposium on Information Control in Manufacturing (INCOM 2015). The paper has been restructured in regards to the order and title of the chapters, and additional information about the integration between devices and services aspects have been added. The introduction and the general structure of the paper now better highlight the contributions of the paper and the uniqueness of the framework. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
12. Analytical solution of magneto-photothermal theory during variable thermal conductivity of a semiconductor material due to pulse heat flux and volumetric heat source.
- Author
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Mahdy, A. M. S., Lotfy, Kh., Hassan, W., and El-Bary, A. A.
- Subjects
HEAT pulses ,THERMAL conductivity ,SEMICONDUCTOR materials ,DEFORMATIONS (Mechanics) ,ANALYTICAL solutions ,THERMOELASTICITY ,HEAT flux - Abstract
In this investigation, the variable thermal conductivity, which depends on a linear function of temperature, is studied during photothermal excitation processes. The influence of the external magnetic field in the context of volumetrically heat source (optically external source) of an elastic semiconductor medium is investigated. The influence of pulse heat flux and thermal memory of the generalized thermoelasticity theory is taken into consideration. The governing equations are obtained in one dimension (1D) by cylindrical coordinates. The interactions between Photo (carrier density)-elastic and magneto-thermal waves are described analytically. The Laplace transform method in 1D is used to obtain the solutions of principal physical field quantities under investigation. The mechanical deformation during the mechanical loads and thermal gradient temperature are applied on the outer surface of the medium. Fourier series expansion and some numerical techniques are used to get the complete solution of physical fields in the physical time-domain. The resulting physical quantities are obtained numerically, discussed, and graphically presented for an example of a semiconductor material. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
13. Aligning geographic entities from historical maps for building knowledge graphs.
- Author
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Sun, Kai, Hu, Yingjie, Song, Jia, and Zhu, Yunqiang
- Subjects
HISTORICAL maps ,KNOWLEDGE graphs ,DEEP learning ,HISTORIC buildings ,GEOGRAPHIC names - Abstract
Historical maps contain rich geographic information about the past of a region. They are sometimes the only source of information before the availability of digital maps. Despite their valuable content, it is often challenging to access and use the information in historical maps, due to their forms of paper-based maps or scanned images. It is even more time-consuming and labor-intensive to conduct an analysis that requires a synthesis of the information from multiple historical maps. To facilitate the use of the geographic information contained in historical maps, one way is to build a geographic knowledge graph (GKG) from them. This paper proposes a general workflow for completing one important step of building such a GKG, namely aligning the same geographic entities from different maps. We present this workflow and the related methods for implementation, and systematically evaluate their performances using two different datasets of historical maps. The evaluation results show that machine learning and deep learning models for matching place names are sensitive to the thresholds learned from the training data, and a combination of measures based on string similarity, spatial distance, and approximate topological relation achieves the best performance with an average F-score of 0.89. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
14. Analysis of various data security techniques of steganography: A survey.
- Author
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Dhawan, Sachin and Gupta, Rashmi
- Subjects
CRYPTOGRAPHY ,DATA security ,RECOMMENDER systems ,DATA analysis ,INTERNET exchange points ,DISCRETE cosine transforms ,DISCRETE wavelet transforms - Abstract
The amount of data exchanged via the Internet is increasing nowadays. Hence, data security is termed as a serious issue while communication of data is processed over the Internet. Everyone needs their data to be safe during the process of communication. Steganography is the process of hiding a message, audio, image, or video by embedding it into another image, audio, message, or video. It is employed to protect secret data from malicious attacks. This paper presents a categorization of the steganography based on technical and non-technical steganography and also categorized based on its domain. Issues related to steganography are quality of stego images, payload capacity, mean square error, structural similarity (SSIM), Image Fidelity (IF), and Normalized Cross-Correlation (NCC) and robustness. Researchers have already done commendable research in the area of image steganography. Still, it is important to feature the upsides and downsides of the current systems of steganography. The objective of the paper is to examine and scrutinize the different algorithms of steganography based on parameters like PSNR, MSE, and Robustness. Based on the analysis of these parameters and all the issues, this paper concludes with recommendations for producing high-quality stego images, high-payload capacity, and robust techniques of steganography. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
15. Status analysis of geographic information science major in Chinese higher education.
- Author
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Zhang, Shuliang, Chen, Ying, Yang, Xin, Xiong, Liyang, Liu, Zhenzhen, and Tang, Guoan
- Subjects
HIGHER education ,INFORMATION science ,EDUCATIONAL sociology ,COLLEGE choice ,UNIVERSITIES & colleges - Abstract
Geographic Information Science (GIS) Major in China has been developing and flourishing for nearly 40 years. Chinese educators have made many achievements on major construction in GIS. However, opportunities and challenges coexist under the new situation of 'Double First-Rate' major construction in China. Thus, investigating and analysing the major status comprehensively are necessary for enhancing the development of the GIS major. This study analyses the enrolment magnitude of undergraduate and postgraduate students, student development, construction of teaching team and professional curriculum construction for GIS majors in mainland Chinese universities. The professional survey results showed that there are about 30,000 undergraduates and 4,000 postgraduates who graduate with GIS degrees every year. However, most of the undergraduates in this major do not take gGIS as their first choice in college major selection. In addition, 190 colleges and universities have set up GIS majors, who have played an important role in the development of GIS and industry. These colleges and universities are mostly concentrated in China's central and eastern regions. The Education and Popularization Science Working Committee of the China Association for Geographic Information Society and the Ministry of Education's Education Committee and other institutions have also organized several meaningful activities to strengthen the guidance of the GIS professional construction. A complete education system has been established to train undergraduates and postgraduates for the development of the geographic information industry in China. [ABSTRACT FROM AUTHOR]
- Published
- 2021
- Full Text
- View/download PDF
16. Being Smarter about Space: Drawing Lessons from Spatial Science.
- Author
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Poorthuis, Ate and Zook, Matthew
- Subjects
DIGITAL technology ,GEOGRAPHIC information systems ,GENTRIFICATION ,DEBATE ,QUANTITATIVE research - Abstract
Copyright of Annals of the American Association of Geographers is the property of Taylor & Francis Ltd and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2020
- Full Text
- View/download PDF
17. Smart Cartographic Background Symbolization for Map Mashups in Geoportals: A Proof of Concept by Example of Landuse Representation.
- Author
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Panchaud, Nadia H. and Hurni, Lorenz
- Subjects
CARTOGRAPHY ,GEOGRAPHIC information systems ,CARTOGRAPHIC materials - Abstract
Geospatial data are now widely available to the general public thanks to geoportals and online mapping platforms. However, creating a map involves more than just combining data layers. Thus we develop cartographic functions for geoportals to support better visual hierarchy in user map mashups. This includes a couple of preparatory steps followed by a smart cartographic background symbolization derived from the original layer style. We evaluate different approaches to background symbolization: greyscale, desaturation, and smart background. The different background symbolization methods are analysed with two concrete map examples and evaluated with a survey. The smart background symbolization developed in this work improves the visual hierarchy of the map mashup by reducing the visual importance of the background layers. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
18. A systematic review of lean implementation approaches: a proposed technology combined lean implementation framework.
- Author
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Rafique, Muhammad Zeeshan, Ab Rahman, Mohd Nizam, Saibani, Nizaroyani, and Arsad, Norhana
- Subjects
LEAN management ,RADIO frequency identification systems ,VALUE stream mapping ,OPERATIONS management ,META-analysis - Abstract
Nowadays, lean implementation seems to be very effective when combined with technologies like radio frequency identification (RFID) but a gap has been observed regarding the availability of certain lean implementation approaches that practice this confluence. Keeping this requirement in view, an extensive systematic literature study has been conducted to first confirm this gap and then to propose an implementation approach by selecting the right approach, methodologies, tools and steps from previous literature. In order to achieve this task, 39 most relevant previous lean implementation approaches have been selected through rigorous search and selection (based on studying their originality, methodology, objectives and limitations) which first confirmed the gap and then enlighten that 56% of previous implementation approaches have utilised 'implementation framework' as the most common approach and the common methodologies utilised were case study and literature review. Moreover, about 25.6% of previous approaches have utilised Value Stream Mapping (VSM) for lean implementation and Technology-Organisation-Environment (TOE) framework was considered as the most appropriate methodology for RFID deployment. So, these statistics were further utilised to invent an implementation framework comprising 21 steps and four implementation phases in which confluence of VSM and TOE has been effectively utilised to achieve successful deployment of technology combined lean. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
19. Attribute trajectory analysis: a framework to analyse attribute changes using trajectory analysis techniques.
- Author
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Zhang, Long and Van de Weghe, Nico
- Subjects
TRAJECTORY measurements ,GEOGRAPHIC spatial analysis ,GEOGRAPHIC information systems ,ATTRIBUTE focusing (Data mining) ,GRAPH theory - Abstract
Trajectory analysis has attracted growing attention in the research field of geography. Beyond traditional moving object trajectories, another type of trajectory exists in which the coordinates are object attributes rather than geographical coordinates. In this paper, a framework to analyse these so-called attribute trajectories is proposed that uses four techniques typically employed in the analysis of moving object trajectories: the Reeb graph, the similarity matrix, the convoy and the mega-convoy. The Reeb graph provides the ability to visualise the temporal dynamics of attribute similarities. The similarity matrix is a supplement of the Reeb graph whose purpose is to visualise the pairwise similarities among the attributes. Moreover, the similarity matrix forms a basis for clustering. The convoy highlights objects whose attributes remain similar for a sufficiently long period. The mega-convoy reduces the number of convoys and reveals their evolutionary histories by merging overlapping convoys. A small real-world meteorological dataset is used as an example to illustrate the attribute trajectory analysis framework and the techniques. This paper aims to form a starting point for applying trajectory analysis techniques in many research fields. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
20. Manual construction of continuous cartograms through mesh transformation.
- Author
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Kronenfeld, Barry J.
- Subjects
CARTOGRAPHY ,ACCURACY ,ALGORITHMS ,TRIANGULATION ,MAPS - Abstract
A computer-assisted framework is proposed to support the manual construction of cartograms. The framework employs a joint triangulation, similar to that used in rubber-sheeting, to define a piecewise affine transformation between map space and cartogram space. This guarantees preservation of all topological relations within and among transformed datasets with insertion of a finite number of points. To support intuitive user control of cartogram appearance, methods are developed to translate generically defined user adjustments of the cartogram into mesh vertex positions on either the source map mesh or cartogram mesh. The framework is implemented in a working prototype application and used to create sample cartograms of the USA and China. Results are compared with cartograms produced using diffusion and carto3f algorithms in terms of accuracy, aesthetic appearance, and approximate construction time. Qualitative aspects of the manual construction process are also discussed. [ABSTRACT FROM AUTHOR]
- Published
- 2018
- Full Text
- View/download PDF
21. Combinational domain-based encryption using FrWT and hyper-chaotic system for biometric data security.
- Author
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Mehta, Garima, Dutta, Malay Kishore, and Kim, Pyung Soo
- Subjects
DATA transmission systems ,FOUR-manifolds (Topology) ,ENCRYPTION protocols ,COMPUTER security ,WAVELET transforms - Abstract
An efficient hyperchaos-based combinational domain encryption scheme for securing iris images during transmission over unsecured data networks or database storage is presented in this article. From the region of interest (ROI) of an iris image, distinctive features are strategically extracted for template creation. The significant part, i.e., the ROI of an iris image, is encrypted in a transformational domain and the nonsignificant region is encrypted in a spatial domain. The advantage of this encryption scheme is increased key space and high degree of security compared to 1-D chaos-based systems. Apart from security, another advantage is reduced computational time compared to conventional encryption schemes implemented in either the spatial or frequency domain. The proposed scheme inherits the advantages of increased key space due to transform orders of the fractional wavelet transform (FrWT) and complex dynamical characteristics of hyperchaos, making the proposed scheme resistant to attacks. The properties of the FrWT and hyperchaos complement each other, making the system efficient and highly robust. Experimental results indicate that the proposed scheme reduces the computational time without compromising the security. Further security analysis is done for various attacks such as differential, statistical, and perceptual attacks, which give promising results and indicate that the proposed encryption scheme is efficient and robust. [ABSTRACT FROM PUBLISHER]
- Published
- 2017
- Full Text
- View/download PDF
22. Sustainable geotourism using digital technologies along a rural georoute in Monsagro (Salamanca, Spain).
- Author
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Martínez-Graña, A. M., Serrano, L., González-Delgado, J. A., Dabrio, C. J., and Legoinha, P.
- Subjects
GEOTOURISM ,DIGITAL technology standards ,RURAL tourism ,GEOLOGICAL maps ,SUSTAINABLE tourism - Abstract
Rural geotourism looks at the natural resources of the territory as a means of promoting a specialized, educational, sustainable tourism. This is an increasingly sought-after activity. This paper presents a rural georoute across a high mountain village, highlighting the remarkable value of the geological heritage of biological trace fossils and physical sedimentary structures exposed on street pavements and façades of houses. A series of tourist georesources were created and implemented: educational and interpretive panels, videos, QR codes, geoapps and games, all of which promote and disseminate the exceptional geological content and the history of the earth through the use of new technologies (smartphones, ipod, etc.). All this is intended as a means to make geotourism a natural tourism, favoring experiences, whilst explaining the natural environment and its temporal and spatial dimensions, offering opportunities for socio-economic development and job creation in rural areas with problems of depopulation. [ABSTRACT FROM AUTHOR]
- Published
- 2017
- Full Text
- View/download PDF
23. Demystifying the secret mission of enhancers: linking distal regulatory elements to target genes.
- Author
-
Yao, Lijing, Berman, Benjamin P., and Farnham, Peggy J.
- Subjects
MOLECULAR structure of chromatin ,GENOME editing ,GENE expression ,TRANSCRIPTION factors ,EPIGENOMICS - Abstract
Enhancers are short regulatory sequences bound by sequence-specific transcription factors and play a major role in the spatiotemporal specificity of gene expression patterns in development and disease. While it is now possible to identify enhancer regions genomewide in both cultured cells and primary tissues using epigenomic approaches, it has been more challenging to develop methods to understand the function of individual enhancers because enhancers are located far from the gene(s) that they regulate. However, it is essential to identify target genes of enhancers not only so that we can understand the role of enhancers in disease but also because this information will assist in the development of future therapeutic options. After reviewing models of enhancer function, we discuss recent methods for identifying target genes of enhancers. First, we describe chromatin structure-based approaches for directly mapping interactions between enhancers and promoters. Second, we describe the use of correlation-based approaches to link enhancer state with the activity of nearby promoters and/or gene expression. Third, we describe how to test the function of specific enhancers experimentally by perturbing enhancer–target relationships using high-throughput reporter assays and genome editing. Finally, we conclude by discussing as yet unanswered questions concerning how enhancers function, how target genes can be identified, and how to distinguish direct from indirect changes in gene expression mediated by individual enhancers. [ABSTRACT FROM PUBLISHER]
- Published
- 2015
- Full Text
- View/download PDF
24. The Regional Economy, Spatial Structure and Regional Urban Systems.
- Author
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Parr, John B.
- Subjects
REGIONAL economics ,URBANIZATION ,INTERNATIONAL economic integration ,LOCATION theory (Geography) ,ECONOMIC structure - Abstract
Copyright of Regional Studies is the property of Routledge and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)
- Published
- 2014
- Full Text
- View/download PDF
25. Gridded cartograms as a method for visualising earthquake risk at the global scale.
- Author
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Hennig, Benjamin D.
- Subjects
NATURAL disasters ,ENVIRONMENTAL mapping ,EARTHQUAKES ,ENVIRONMENTAL risk ,PHYSICAL environment ,NATURE ,VISUALIZATION - Abstract
The assessment of natural events that can turn into disasters where people live is usually accompanied by maps visualising the specific topic in its spatial setting and putting the physical environment into the main focus. Suchconventionalmapping approaches, however, can often fail to give an intuitive understanding of the underlying quantitative dimension of the associated risk to people and a fuller appreciation of the interrelation between humans and their natural environment. The method presented here demonstrates an alternative way of mapping environmental risk. A gridded cartogram approach is introduced and illustrated with examples drawn from data documenting globally significant earthquakes that have occurred since 2150 BC.Gridded cartogramsare a new map projection. They are created by starting with an equally distributed grid onto which a density-equalising cartogram technique is applied. Each individual grid cell is resized according to specific quantitative information. The underlying grid ensures the preservation of an accurate geographic reference to therealworld. It allows gridded cartograms to be used as basemaps, new projections, onto which other information can be mapped. Earthquake intensity on a gridded population cartogram highlights those zones where most people live in these risk environments and minimises information about where earthquakes still occur, but where they matter less for human populations. Gridded cartograms also allow any other quantitative data to be used in the actual transformation. This is demonstrated with gridded cartograms from earthquake intensity data, resulting in very unusual depictions and new perspectives of the surface of the planet. [ABSTRACT FROM AUTHOR]
- Published
- 2014
- Full Text
- View/download PDF
26. Visualizing Travel Patterns with a GPS Dataset: How Commuting Routes Influence Non-Work Travel Behavior.
- Author
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Wang, Xiaoguang, Grengs, Joe, and Kostyniuk, Lidia
- Subjects
GLOBAL Positioning System ,GEOGRAPHIC information systems ,COMMUTING ,TRAVEL ,DISTANCES - Abstract
This paper examines the spatial patterns of non-work activities for 34 drivers in the Southeast Michigan region. Capitalizing upon a unique global positioning systems (GPS) dataset and GIS visualization techniques, this study quantifies the spatial distributions of non-work activities for drivers with different commuting distances, and for non-work activities that are chained in different types of travel (commute travel vs. non-commute travel). We find a strong dependence of non-work activity locations on commuting distances, and an influence of commuting routes on non-work activities chained in all types of travel. The results underline the importance of commuting routes in shaping the spatial configuration of non-work activities. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
27. Assessment of surface and subsurface waterlogging, water level fluctuations, and lithological variations for evaluating groundwater resources in Ganga Plains.
- Author
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Pandey, ArvindChandra, Singh, SurajKumar, Nathawat, M.S., and Saha, Dipankar
- Subjects
WATERLOGGING (Soils) ,WATER levels ,GROUNDWATER ,PETROLOGY ,HYDRAULIC measurements - Abstract
In the present study, the multi-temporal satellite images of IRS P6 LISS III were used to map waterlogging dynamics over different seasons. An area of 594.36 km2(6.75%) and 4.17 km2(0.04%) was affected by surface waterlogging during pre and postmonsoon season, respectively. The average annual groundwater level fluctuations were calculated using 18 years (1990–2007) pre and postmonsoon groundwater level data to identify the areas which are under groundwater induced waterlogging conditions. The soil map clearly indicates that salinity and sodicity exhibit the highest severity and occur in areas with shallow groundwater levels. The hydrogeomorphical units mapped using IRS P6 LISS III satellite images are flood plain, alluvial plain, paleochannels, and oxbow lakes. The study revealed that 44.65% areas have very good to excellent groundwater resources. The litholog data clearly indicate an alternating sequence of clay and sand in which deep aquifers made up of coarse sand would be best suited for adequate water supply and good groundwater quality. The integrated study utilizing digital spatial data pertaining to waterlogging, soil salinity, water level fluctuation, and lithological variation proved that planning of any surface and subsurface water resources development activity should be taken up after assessments of said parameters. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
28. A fast, free-form rubber-sheet algorithm for contiguous area cartograms.
- Author
-
Sun, Shipeng
- Subjects
TOPOLOGY ,SPATIAL data structures ,GEOGRAPHIC spatial analysis ,GEOLOGICAL statistics ,GENETIC algorithms - Abstract
This article presents a fast, free-form rubber-sheet (Carto3F) algorithm for the construction of contiguous area cartograms. Rubber-sheet algorithms are influential and popular because of their conceptual simplicity. Existing rubber-sheet algorithms, however, tend to be algorithmically inefficient and computationally slow. More critically, they cannot completely preserve topology. Carto3F specifically improves rubber-sheet algorithms in these two aspects. First, with a spatial structure of quadtree and a mathematical condition for topological equivalence, Carto3F can prevent topological errors and guarantees topological integrity. Second, Carto3F is designed with efficiency as a priority. Its efficiency is primarily gained through using the auxiliary quadtree to reduce the number of points to be transformed. Furthermore, Carto3F allows parallel computation and can fully take advantage of the increasingly common multi-core, multi-thread processors. Based on the mathematical analysis, Carto3F also mitigates the effect of force cancellation that is inherent in rubber-sheet algorithms. On a computer equipped with a 2.4-GHz quad-core CPU, Carto3F can produce quality population cartograms of the United States, China, and the world within 1 second, 18 seconds, and 8 minutes, respectively. Quantitative measures show that Carto3F outperforms the optimized rubber-sheet algorithm and the diffusion algorithm in both transformation effectiveness and computational efficiency. [ABSTRACT FROM PUBLISHER]
- Published
- 2013
- Full Text
- View/download PDF
29. Which children can find a way through a strange town using a streetmap? – results of an empirical study on children's orientation competence.
- Author
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Hemmer, Ingrid, Hemmer, Michael, Kruschel, Katja, Neidhardt, Eva, Obermaier, Gabriele, and Uphues, Rainer
- Subjects
PERFORMANCE in children ,INTELLIGENCE testing in children ,SCHOOL children ,ROAD maps ,EMPIRICAL research ,MENTAL rotation ,TRAINING - Abstract
This article relates about some results of an interdisciplinary research project analyzing influencing factors of children's spatial orientation competence in real space carried out by geography educators and psychologists. The focus is on the concept of representation as a theoretical foundation. The research design for collecting data of independent and dependent variables (map-based orientation competence, MBO), and the self-developed measuring instrument are explained. Altogether, 328 pupils of third, fourth, and fifth grade (aged 8–12 years) were tested. The orientation competence of children in strange spaces was slightly above the average, and grew with age. The most spectacular increase was detected on the transition from third to fourth grade. Additionally, boys scored higher than girls. The results also showed that along with age and gender, spatial intelligence (mental rotation) and previous knowledge shape MBO. A limited influence can be attributed to self-concept and previous experiences, while interest has no influence on MBO at all. [ABSTRACT FROM AUTHOR]
- Published
- 2013
- Full Text
- View/download PDF
30. Mapping of a boundary line from remote sensing: an applied case study on Little Okinawa Island.
- Author
-
Shyu, Tian-Yow, Yeh, Hui-Chung, and Liu, Chung-Chih
- Subjects
GEOGRAPHIC boundaries ,REMOTE sensing ,TECHNOLOGICAL innovations ,REMOTE-sensing images ,MAP scales - Abstract
Due to rapid technological improvements, it has become easy to acquire remote-sensing images. Therefore, mapping through remote sensing has become convenient and readily available, which saves time and resources. Nevertheless, some key steps need to be performed during the mapping process, including line generalization and smoothing. The former involves retaining the key characteristics of the original map, whereas the latter removes any unnecessary points; both procedures improve the quality of the final map. Many different theoretical and methodological approaches to smoothing and generalization have been proposed by researchers. In this study, we used the Douglas–Peucker method and Topfer and Pillewizer's law to obtain the optimum threshold length. To achieve this threshold, the following were carried out: (1) small-scale line generalization and (2) line generalization by an intermediate map scale transform. From the line generalization and smoothing process, a boundary line map of Little Okinawa Island was subsequently produced. The results of our study may serve as a valuable tool for future remote-sensing mapping tasks. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
31. Analysing the impact of anthropogenic activities on waterlogging dynamics in Indo-Gangetic Plains, northern Bihar, India.
- Author
-
Pandey, A. C., Singh, Suraj Kumar, and Nathawat, M. S.
- Subjects
WATERLOGGING (Soils) ,TOPOGRAPHIC maps ,REMOTE-sensing images ,IRRIGATION projects ,AGRICULTURAL intensification - Abstract
Historical to recent spatial variability in surface waterlogging was evaluated using a topographical map of 1925 and satellite images of 1975, 1988, 1999 and 2006. A visual satellite image interpretation technique was used to delineate waterlogged areas and associated infrastructure details. Areas of 31, 73.89, 163.86, 143.61 and 102.59 km2 were found to be affected by surface waterlogging during 1925, 1975, 1988, 1999 and 2006, respectively. A sharp increase in waterlogging from 1925 to 1975 is attributed to the functioning of irrigation projects in the region. The very high areas under waterlogging during 1988 and 1999 reflect intensification of agricultural activity. A substantial decrease in waterlogging during 2006 is attributed to the implementation of government wasteland reclamation measures. The area statistics of waterlogging computed for the buffer zone along select features showed that the maximum waterlogging occurs along canals and railways followed by rivers and the least along roads. [ABSTRACT FROM AUTHOR]
- Published
- 2012
- Full Text
- View/download PDF
32. Map-based multicriteria analysis to support interactive land use allocation.
- Author
-
Arciniegas, Gustavo, Janssen, Ron, and Omtzigt, Nancy
- Subjects
REAL property ,REAL estate development ,LANDSCAPE assessment ,SANITARY landfills ,REAL estate business - Abstract
This article focuses on the use of map-based multicriteria analysis to develop a negotiation support tool for land use allocation. Spatial multicriteria analysis is used to make explicit trade-offs between objectives and to provide guidance and feedback on the land use changes negotiated by the participants. Digital maps are the means of communication among workshop participants, and an interactive mapping device (the ‘Touch table’) is used as the interface. Participants are informed about the relevant trade-offs on the map and use this information to change the land use maps. The approach is tested during a negotiation session as part of the land use planning process of the Bodegraven polder, a peat meadow area in the Netherlands. [ABSTRACT FROM AUTHOR]
- Published
- 2011
- Full Text
- View/download PDF
33. The Inverse Distance Weighted interpolation method and error propagation mechanism – creating a DEM from an analogue topographical map.
- Author
-
Achilleos, G.A.
- Subjects
DIGITIZATION ,INTERPOLATION ,DIGITAL elevation models ,STATISTICAL sampling ,RELIEF models - Abstract
Interpolation procedures are widely used in science, especially in sciences that involve spatial data and continuous phenomena that can be depicted on a continuous spatial surface. Interpolation makes use of accurate and qualitative sampling data in order to produce a continuous representation of the phenomenon in question. The accuracy of the data used for interpolation directly affects the results. This research examines error propagation within the Inverse Distance Weighted (IDW) method, applied as a means of representing the earth's relief. Interpolation of a DEM within contours on a topographical map is considered to be a three-stage procedure. The first stage is the digitising of the contours depicted on the analogue map. Errors involved in this stage are propagated to the second stage, the geometric transformation of coordinates of these digitised contours. Additional errors due to the application of the transformation model are embedded within the results thus obtained. Finally, the errors are propagated to the third stage. Errors are magnified due to the application of an interpolation method, in our case, the IDW method. Any stage of the procedure can be considered separately. The procedure aims to cover the situation where a DEM is created using an analogue topographical map in conjunction with the IDW interpolation method. [ABSTRACT FROM PUBLISHER]
- Published
- 2011
- Full Text
- View/download PDF
34. A Novel Algorithm of Buffer Construction Based on Run-length Encoding.
- Author
-
Jiechen Wang, Can Cui, Yingxia Pu, Jinsong Ma, and Gang Chen
- Subjects
ALGORITHMS ,GRIDS (Cartography) ,BUFFER zones (Ecosystem management) ,GEOGRAPHIC information systems ,DIGITIZATION ,VECTOR data - Abstract
This paper presents an algorithm of buffer construction incorporating run-length encoding and the idea of raster overlay method. In traditional raster methods, the buffer target is traced and scanned using a 'brush', the width of which is equal to the buffer distance. During this process, the brushed raster grids are marked. Then by carrying out dynamic calculation on these marked grids, the buffer zone, constituted of grids, would be generated. Finally, the desired boundary of the buffer zone could be obtained through vectorisation. Considering the obvious drawbacks of raster data in computing efficiency and storage capacity, this paper puts forward the idea of storing raster data by means of run-length encoding, on which the raster-based operations are carried out. In order to improve the spatial precision, the borderlines of each run-length unit are recorded in the data of real type. The tests and analyses indicate that this algorithm has integrated advantages with respect to time complexity, space complexity and computational accuracy. [ABSTRACT FROM AUTHOR] - Published
- 2010
- Full Text
- View/download PDF
35. You-Are-Here Maps: Creating Spatial Awareness through Map-like Representations.
- Author
-
Klippel, Alexander, Hirtle, Stephen, and Davies, Clare
- Subjects
SPACE perception ,MAP reading ,MENTAL orientation ,MAPS ,SPATIAL behavior - Abstract
The article discusses the concept of spatial awareness in using you-are-here maps. Spatial knowledge is categorized into landmark knowledge, route knowledge and survey knowledge. The authors claim that spatial awareness is an important concept for successful orientation, wayfinding and navigation. They add that the ability to create element-to-element correspondence within and between maps is relevant when using a map to create spatial awareness. Overview of papers about spatial awareness published within the issue is also presented.
- Published
- 2010
- Full Text
- View/download PDF
36. You Are Where? The Function and Frustration of You-Are-Here (YAH) Maps.
- Author
-
Montello, Daniel R.
- Subjects
MAPS ,NAVIGATION ,MENTAL orientation ,MAP reading ,GEOGRAPHY - Abstract
In this article, I define you-are-here (YAH) maps and consider their fundamental characteristics from cartographic and psychological perspectives. I then review the basic phenomenon of the alignment effect, including why it happens and how it may be overcome; I also consider exceptions to the alignment effect. Finally, I briefly note some special issues with YAH maps that arise when a person uses a digital navigation system. [ABSTRACT FROM AUTHOR]
- Published
- 2010
- Full Text
- View/download PDF
37. Errors within the Inverse Distance Weighted (IDW) interpolation procedure.
- Author
-
Achilleos, Georgios
- Subjects
INTERPOLATION ,SCIENCE ,APPROXIMATION theory ,NUMERICAL analysis ,EARTH (Planet) - Abstract
Interpolation procedure is broadly used in sciences that are concerned with spatial data and continuous phenomena that can be depicted on a spatial surface. Interpolation makes use of sampling data, which is accurate and qualitative, in order to produce a continuous representation of the phenomenon in question. The data's accuracy is transferred by the procedure to its results and should be known. This paper examines error propagation by the interpolation procedure, using the Inverse Distance Weighted (IDW) method in the case of the Earth's relief. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
38. An initial formal model for spatial data infrastructures.
- Author
-
Hjelmager, Jan, Moellering, Harold, Cooper, Antony, Delgado, Tatiana, Rajabifard, Abbas, Rapant, Petr, Danko, David, Huet, Michel, Laurent, Dominique, Aalders, Henri, Iwaniak, Adam, Abad, Paloma, Düren, Ulrich, and Martynenko, Alexander
- Subjects
DISTRIBUTED computing ,ELECTRONIC data processing ,SPATIAL data infrastructures ,GEOGRAPHIC information systems ,CARTOGRAPHY ,GRAPHIC methods - Abstract
The Commission on Spatial Data Standards of the International Cartographic Association is working to define formal models and technical characteristics of Spatial Data Infrastructures (SDI). To date, this work has been restricted to the Enterprise and Information Viewpoints from the ISO Reference Model for Open Distributed Processing standard. The Commission has developed models for these two viewpoints. These models describe how the different parts of an SDI fit together in the viewpoints in question. These models should be seen as a contribution towards the overall model of the SDI and its technical characteristics. During the model development process, the roles of the different Actors in an SDI in the Enterprise and Information Viewpoints have also been identified in Use Case diagrams of an SDI. All the models have been developed using the Unified Modeling Language. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
39. GIS-based multicriteria spatial modeling generic framework.
- Author
-
Chakhar, S. and Mousseau, V.
- Subjects
GEOGRAPHIC information systems ,INFORMATION resources ,UNITS of measurement ,PROTOTYPES ,GEOGRAPHY ,GEODATABASES - Abstract
Multicriteria analysis is a set of mathematical tools and methods allowing the comparison of different alternatives according to many criteria, often conflicting, to guide the decision maker towards a judicious choice. Multicriteria methods are used in spatial context to evaluate and compare spatial decision alternatives, often modeled through constraint-based suitability analysis and represented by point, line, and polygon features or their combination, and evaluated on several space-related criteria, to select a restricted subset for implementation. Outranking methods, a family of multicriteria methods, may be useful in spatial decision problems, especially when ordinal evaluation criteria are implied. However, it is recognized that these methods, except those devoted to multicriteria classification problems, are subject to computational limitations with respect to the number of alternatives. This paper proposes a framework to facilitate the incorporation and use of outranking methods in geographical information systems (GIS). The framework is composed of two phases. The first phase allows producing a planar subdivision of the study area obtained by combining a set of criteria maps; each represents a particular vision of the decision problem. The result is a set of non-overlapping spatial units. The second phase allows constructing decision alternatives by combining the spatial units. Point, line and polygon feature-based decision alternatives are then constructed as an individual, a grouping of linearly adjacent or a grouping of contiguous spatial units. This permits us to reduce considerably the number of alternatives, enabling the use of outranking methods. The framework is illustrated through the development of a prototype and through a step-by-step application to a corridor identification problem. This paper includes also a discussion of some conceptual and technical issues related to the framework. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
40. Constructing Time-Scaled Maps: Switzerland from 1950 to 2000.
- Author
-
Axhausen, K. W., Dolci, C., Fröhlich, Ph., Scherer, M., and Carosio, A.
- Subjects
MAPS ,MATHEMATICS ,MATHEMATICAL series ,ALGEBRA - Abstract
The article discusses the construction of a time-scaled maps series for Switzerland documenting the shrinking of the country since 1950. It describes underlying network models and the mathematical approach employed for the necessary rescaling. In conclusion, it presents the maps and discusses how the country was shrunk by half. [ABSTRACT FROM AUTHOR]
- Published
- 2008
- Full Text
- View/download PDF
41. A critical evaluation of location based services and their potential.
- Author
-
Raper, Jonathan, Gartner, Georg, Karimi, Hassan, and Rizos, Chris
- Subjects
MOBILE communication systems ,INFORMATION science ,CARTOGRAPHY ,INTERFACES (Physical sciences) ,RESEARCH - Abstract
This Editorial lead article for the Journal of Location Based Services surveys this complex and multi-disciplinary field and identifies the key research issues. Although this field has produced early commercial disappointments, the inevitability that pervasive location-aware services on mobile devices will emerge means that much research is needed to inform these developments. The article reviews firstly: the science and technology of positioning, geographic information science, mobile cartography, spatial cognition and interfaces, information science, ubiquitous computing; and secondly the business, content and legal, social and ethics aspects, before synthesising the key issues for this new field. [ABSTRACT FROM AUTHOR]
- Published
- 2007
- Full Text
- View/download PDF
42. The Palestine Exploration Fund Map (1871–1877) of the Holy Land as a Tool for Analysing Landscape Changes: the Coastal Dunes of Israel as a Case Study.
- Author
-
Levin, Noam
- Subjects
MAPS ,GEOGRAPHY ,TOPOGRAPHIC maps ,HISTORICAL maps - Abstract
The Palestine Exploration Fund (PEF) maps (1871–1877) are highly praised for their accuracy and completeness; however, no systematic analysis of their accuracy has been done to date. To study the potential of these 1:63,360 maps for a quantitative analysis of land cover changes over a period of time, I have compared them to 20th century topographic maps. The map registration error of the PEF maps was 74.4 m using 123 control points of trigonometrical stations and a 1st order polynomial. The median RMSE of all control and test points (n = 1104) was 153.6 m. As a case study of land cover changes, the area of coastal dunes as shown on the PEF maps was compared with that shown on British Mandate 1:20,000 topo-cadastral maps from c. 1930. In five of the six areas analysed, the yearly dunes movement rate was above the estimated annual error due to data resolution (2.96 m/year). The rate of dune movement south of Acre was found to be between 3.9 and 6.3 m/year (depending on the method used for map registration) between 1874 and 1930. Care should be taken when analysing historical maps, as it cannot be assumed that their accuracy is consistent at different parts or for different features depicted on them. [ABSTRACT FROM AUTHOR]
- Published
- 2006
- Full Text
- View/download PDF
43. Vegetation of the greater Maya Mountains, Belize.
- Author
-
Penn, Malcolm G., Sutton, David A., and Monro, Alex
- Published
- 2004
- Full Text
- View/download PDF
44. Systematic Assessment of Maps as Source Information in Landscape-change Research.
- Author
-
Vuorela, Niina, Alho, Petteri, and Kalliola, Risto
- Subjects
MAP reading ,LANDSCAPE changes - Abstract
A methodology is proposed for systematic map assessment to contribute to landscape-change research. Two major topic areas are dealt with, namely: content, quality and usefulness of landscape information on different maps; and methods used in the spatial conversion of maps into digital systems (e.g. geographical information systems). The major focus is on information about physical landscape characteristics (e.g. land cover) and land uses. The approach was tested using a sequence of nine large- and medium-scale basic maps of the island of Ruissalo in SW Finland from between 1690 and 1998. Fundamental differences were found in the thematic consistency of landscape information, mainly related to the scale, purpose and generalization of landscape information on different maps. Spatial matching was tested for a set of three old maps using four image rectification functions. The results showed that spatial matching of old maps is difficult, and success in rectification is influenced by many factors. Evaluation and selective transformation of landscape information from maps and the use of supportive information from other sources can assist in landscape-change analysis based on map sequences. [ABSTRACT FROM AUTHOR]
- Published
- 2002
- Full Text
- View/download PDF
45. Evaluation of ERS‐1 SAR Data for Agricultural Crop Monitoring in India.
- Author
-
Chakraborty, M., Parihar, J. S., Manjunath, K. R., Kundu, N., and Panigrahy, S.
- Published
- 2002
- Full Text
- View/download PDF
46. Mathematical basis for large scale GIS and terrestrial digital products.
- Author
-
Yuju, Hu, Peng, Hu, Yanian, Wu, Chuanyong, Yang, and Guojian, Li
- Abstract
The problem of spatial mathematical basis has been encountered by both large scale GIS and spatial digital products theoretically and practically. It is also a basic problem in the development of the whole geo-information science. After analyzing the status quo and the limitations of the space mathematical base of GIS, this paper points out definitely that the geodetic coordinate system is uniform, which can show the location of any point of the global exactly and uniquely in form of ( B, L, H) and is the most proper reference system of largescale GIS and Digital Earth. Moreover, this paper also puts forward a set of practical model of the standard “map projection”. Finally, this paper introduces a DRG system based on this model. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
47. Fuzzy methods for categorical mapping with image-based land cover data.
- Author
-
Zhang, Jingxiong and Stuart, Neil
- Subjects
FUZZY systems ,GEOGRAPHY - Abstract
This paper presents an approach to capturing and representing the uncertainty inherent in any attempt to classify continuously varying geographical phenomena into discrete categories. This uncertainty is captured during a visual photo-interpretation and a computerised image classification process and encoded as a series of fuzzy surfaces. These store the fuzzy membership values (FMVs) of each location to all candidate classes in a desired classification scheme. These surfaces are used to explore graphically the underlying variations in the level of certainty of assigning candidate classes to individual locations. A technique is presented that analyses these FMV surfaces by applying alpha-cuts (thresholds) to derive a series of traditional categorical maps in the form of vector polygons. The relative certainty of the attribute classification is used to determine an appropriate Epsilon band width around boundary lines separating different land cover classes on the resulting categorical map. The approach is tested on the practical problem of producing categorical maps of land cover for a suburban area. Uncertainty surfaces are derived for land cover classifications created both from photogrammetric interpretation and from satellite image classification. A series of categorical maps of land cover are derived for different minimum levels of certainty in the attribute classification. [ABSTRACT FROM AUTHOR]
- Published
- 2001
- Full Text
- View/download PDF
48. Subglacial topography of Jutulstraumen outlet glacier, East Antarctica, mapped from ground-penetrating radar, optical and interferometric synthetic aperture radar satellite data.
- Author
-
MELVOLD, KJETIL and ROLSTAD, CECILIE EIE
- Subjects
GLACIERS ,GLACIAL climates - Abstract
The bed topography of Jutulstraumen is of interest in connection with glaciological modelling for climatic and geological studies. During the Norwegian Antarctic Research Expedition 1996/97 (NARE 96/97) 971 km of bed topography profiles were mapped using ground-penetrating radar (GPR) and a global positioning system (GPS). As additional information to the GPR data for the map compilation, surface features connected to the bed topography were identified in optical satellite images, and relative velocities derived from interferometric synthetic aperture radar (INSAR) data were interpreted using principles of ice flow related to the bed topography. Grids (250 x 250 m) covering the area 73° to 71°S, 0° to 4°E of bed topography and ice thickness were developed. Several observations are confirmed by the independent data sets. The Jutulstraumen outlet glacier shows extreme topography with subglacial plateaus and deep valleys due to faulting. A previously unmapped valley in connection with the fault system is identified. The data sets provide evidence of a grounding line position 6-20 km further inland than previously expected, and a trough occurs 60 km up-glacier from this position. [ABSTRACT FROM AUTHOR]
- Published
- 2000
- Full Text
- View/download PDF
49. Performance of ferroelectric based tunable capacitors as a function of electrode geometry.
- Author
-
Rivkin, T. V., Carlson, C. M., Parilla, P. A., and Ginley, D. S.
- Published
- 2000
- Full Text
- View/download PDF
50. BULLETIN.
- Published
- 1994
- Full Text
- View/download PDF
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