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This study analyzed data from the quarterly results of water quality monitoring in the State of Santa Catarina (Southern Brazil) from the Qualiágua Program. The results present water quality collections carried out in 2019-2021 of 23 analytical parameters in 40 municipalities of the State. The Principal Component Analysis (PCA) technique was applied to the analyzed parameters and to verify sources of contamination. The data on land use of the hydrographic basins of each monitoring point were also analyzed. The results showed that electrical conductivity, total and dissolved solids and chloride concentration are responsible for most of the data variability, having more influence at monitoring points close to the ocean. On the other hand, nitrate and turbidity are influenced by soil management due to land use. Total phosphorus, ammoniacal nitrogen and thermotolerant coliforms had a greater relationship with urban areas. The results provide helpful information for decision-making processes related to public policies for water uses in the State. [ABSTRACT FROM AUTHOR]

The fractal behaviour of gravity field elements was investigated. Particularly, the geoidal heights, gravity anomalies and vertical deflection components were considered. Such data were synthesized from the ultra-high degree SGG-UGM-1 geopotential model. The Egyptian Territory was selected as the study area. To supplement the results, parallel fractal analyses were performed on the GTM3A, Earth2012 and SRTM30 terrain data. The regularization, variogram and global Power Spectral Density (PSD) concepts were applied as different tools for fractal analysis. Consistent fractal dimensions resulted from the regularization and variogram algorithms. These two algorithms ensured the fractalness of the gravitational signals, including the geoidal height. The global PSD algorithm failed to give meaningful fractal dimensions for the topography and geoidal heights. However, it yielded realistic dimensions for the other elements. So, fractal dimensions could characterize the roughness and spatial precisions of different gravitational data. Also, multifractal modeling of the geopotential might be a promising task. [ABSTRACT FROM AUTHOR]

Lidar and other remotely sensed data such as UAV photogrammetric data capture are being collected and utilized for roadway design on an increasing basis. These methods are desirable over conventional survey due to their efficiency and cost-effectiveness over large areas. A high degree of relative accuracy is achievable through the establishment of survey control. In this case study, elevations (z-values) derived from mobile-terrestrial lidar, aerial lidar, and UAV photogrammetric capture collected with survey control were statistically compared to conventionally surveyed elevations. A cost comparison of the methods is also included. Each set of z-values corresponds to a discrete horizontal point originally part of the conventional survey, collected as cross-sections. These cross-sections were surveyed at three approximate tenth-mile sample locations along US-30 near Georgetown, Idaho. The cross-sections were collected as elevational accuracy verification, and each sample location was selected as an area where the mobile-terrestrial lidar in particular was expected to have more difficulty achieving accuracy off the road surface. Processing and analysis were performed in Esri ArcMap 10.6, and all data were obtained from the Idaho Transportation Department, District 5. Overall, the aerial lidar elevations were found to be closest to conventionally surveyed elevations; on road surface and level terrain, mobile-terrestrial and UAV photogrammetric capture elevations were closer to the conventionally measured elevations.

A package to generate the symbolic dynamic equations describing the relation between forces and movements for serial mechanical linkages with rigid constituents is presented. The relative movement between the rigid parts is assumed to be either a rotation about an axis or a translation along an axis. Two algorithms are implemented, a Lagrange-Euler method and a Newton-Euler method. The former can be used to solve both the inverse and the forward dynamics problems, while the latter requires fewer arithmetical operations but only allows solution of the inverse dynamics problem. Two test examples are presented, the double pendulum and the modified Stanford manipulator.

A general purpose Navier - Stokes solver has been applied to atmospheric flow on microscale. For flat terrain the model produces the well known logarithmic profile in the surface layer and describes the effect of roughness change. At Askervein Hill, good agreement between model results and measurements is observed also behind the hilltop, where linearized models overpredict the wind speed.

The digital elevation products produced by the Shuttle Radar Topography Mission (SRTM) are disseminated with different resolutions. This study investigates the differences in information content between different resolutions. Three 1° cells are selected to represent flat area, moderate terrain, and mountain ranges. All of these cells are located in the continental territory of the United States. The theory of information loss caused by the sampling density is shown with the increasing deviation from the reference in the experiment. The error resulting from bilinear interpolation is also assessed. The experimental result also indicates that if the 1-arcsecond SRTM, digital elevation model (DEM) is released for global coverage, the height accuracy would be improved over the 3-arcsecond product. [ABSTRACT FROM AUTHOR]

For reasons of documentation, management and certification there is a high interest in efficient inventories of palm plantations on the single plant level. Recent developments in unmanned aerial vehicle (UAV) technology facilitate spatial and temporal flexible acquisition of high resolution 3D data. Common single tree detection approaches are based on Very High Resolution (VHR) satellite or Airborne Laser Scanning (ALS) data. However, VHR data is often limited to clouds and does commonly not allow for height measurements. VHR and in particular ALS data are characterized by high relatively high acquisition costs. Sperlich et al. (2013) already demonstrated the high potential of UAV-based photogrammetric point clouds for single tree detection using pouring algorithms. This approach was adjusted and improved for an application on palm plantation. The 9.4ha test site on Tarawa, Kiribati, comprised densely scattered growing palms, as well as abundant undergrowth and trees. Using a standard consumer grade camera mounted on an octocopter two flight campaigns at 70m and 100m altitude were performed to evaluate the effect Ground Sampling Distance (GSD) and image overlap. To avoid commission errors and improve the terrain interpolation the point clouds were classified based on the geometric characteristics of the classes, i.e. (1) palm, (2) other vegetation (3) and ground. The mapping accuracy amounts for 86.1% for the entire study area and 98.2% for dense growing palm stands. We conclude that this flexible and automatic approach has high capabilities for operational use. [ABSTRACT FROM AUTHOR]

Analyzing the distance visible to a driver on a highway is important for traffic safety, especially in manoeuvres such as emergency stops, when passing another vehicle, or when vehicles cross at intersections. Software that calculates highway distances visible to a driver has been developed. This software is supported by a geographic information system (GIS) and can use a trajectory defined by points obtained with a global navigation satellite system (GNSS) receiver instead of relying on project information. The software includes specific tools for studying shortcomings in three-dimensional (3D) alignment; mainly, this pertains to divings. In this article, the software and its application to a case study are presented. The results are compared with those obtained using an existing validated procedure. [ABSTRACT FROM AUTHOR]

Finding which triangle in a planar or 2.5D triangle mesh contains a query point (so-called point location problem) is a frequent task in geosciences, especially when working with triangulated irregular network models. Usually, a large number of point locations has to be performed, and so there is a need for fast algorithms having minimal additional memory requirements and resistant to changes in the triangulation. So-called walking algorithms offer low complexity, easy implementation, and negligible additional memory requirements, which makes them suitable for such applications. In this article, we focus on these algorithms, summarize, and compare them with regard to their use in geosciences. Since such a summary has not been done yet, our article should serve those who are dealing with this problem in their application to decide which algorithm would be the best for their solution. Moreover, the influence of the triangulation type on the number of the visited triangles is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Analyzing the distance visible to a driver on the highway is important for traffic safety, especially in maneuvers such as emergency stops, when passing another vehicle or when vehicles cross at intersections. This analysis is necessary not only in the design phase of highways, but also when they are in service. For its use in this last phase, a procedure supported by a Geographic Information System (GIS) has been implemented that determines the highway distances visible to the driver. The use of a GIS allows the sight distance analysis to be integrated with other analyses related to traffic safety, such as crash and design consistency analyses. In this way, more complete analyses could be made and costs shared. Additionally, with the procedure proposed it is possible to use data regarding the trajectory of a vehicle obtained on a highway with a Global Positioning System (GPS) device. This application is very useful when highway design data are not available. The procedure developed and its application in a case study are presented in this article. [Copyright &y& Elsevier]

The number of flood disasters has increased worldwide in recent decades. Identifying the optimal resolution or scale at which to represent digital terrain models (DTMs) is critical in order to improve our ability to accurately and efficiently model floods. Few studies have attempted to compare flood modeling results using different resolutions of DTMs in divergent environments. In this study flooding on the Tar River in the coastal plains and the Watauga River in the mountains of North Carolina were modeled using hydrologic information obtained following Hurricanes Floyd and Ivan. The effectiveness of DTMs derived from light detection and ranging and United States Geological Survey elevation data at commonly available resolutions in North Carolina were assessed. A quantitative diagnostic method based on measuring the distance flooded along transects was applied for evaluating the horizontal extent and internal pattern of flooding. The use of additional diagnostic metrics (area, volume, and shape) along with a visual graphic assessment enhanced the evaluation of flood modeling results. The extent and internal pattern of flooding in the low-relief coastal plains was found to be especially sensitive to the representation of terrain, and in the mountains 30×30-m data regardless of source were found to be dramatically unsuitable for flood modeling. [ABSTRACT FROM AUTHOR]

This article assesses the accuracy of the terrain models of Joachim Eugen Müller (1752–1833) in relation to modern digital elevation data using non-contact 3D digitizing techniques. The results are objective testimony to the skill and endeavour of Joachim Eugen Müller. Using techniques primitive by modern standards, Müller provided Johann Henry Weiss (1758–1826) with data of hitherto unparalleled quality that were essential to the production of the Atlas Suisse par Meyer et Weiss. The results also demonstrate that non-contact 3D digitizing techniques not only provide a suitable data-capture method for solid terrain model analysis but are also a means of preserving digital facsimiles of such precious artefacts. [ABSTRACT FROM AUTHOR]

Abstract: Two- and three-dimensional (2D/3D) hydrodynamic models require the geometric description of river bathymetry and its surrounding area as a continuous surface. These surface representations of river systems are also required in mapping flood inundation extents. Creating surface representations of river systems is a challenging task because of issues associated with interpolating river bathymetry, and then integrating this bathymetry with surrounding topography. The objectives of this paper are to highlight key issues associated with creating an integrated river terrain, and propose GIS techniques to overcome these issues. The following techniques are presented in this paper: mapping and analyzing river channel data in a channel fitted coordinate system; interpolation of river cross-sections to create a 3D mesh for main channel; and integration of interpolated 3D mesh with surrounding topography. These techniques are applied and cross-validated by using datasets from Brazos River in Texas, Kootenai River in Montana, and Strouds Creek in North Carolina. Creation of a 3D mesh for the main channel using a channel-fitted coordinate system and subsequent integration with surrounding topography produces a coherent river terrain model, which can be used for 2D/3D hydrodynamic modeling and flood inundation mapping. Although techniques presented in this paper produce better results compared to existing GIS methods, the linear approach has some limitations which can be overcome by accounting for channel meanders, sinuosity and thalweg location. [Copyright &y& Elsevier]

Visualization can be of significant value in improving the verification, validation, and communication of discrete-event simulation models of construction operations, which in turn can make the models more credible and thus useful in operations planning. The presented work extends the state-of-the-art of visualizing simulation models of construction operations in three-dimensions. The writers present efficient methods and a tool, ViTerra, that can be used to automatically generate photorealistic, digital, three-dimensional (3D) terrain computer-aided design databases to represent construction job sites in animations of simulated construction processes. The work capitalizes on the availability of detailed topographical and aerial imagery data that are readily available in digital format from several government and private organizations. In addition to automated terrain generation techniques, the presented work implements animation methods to describe the evolution of virtual jobsites by depicting deformations to the visualized terrains in response to common construction operations such as earthmoving and trenching. The writers’ first contribution alleviates the need to manually create 3D terrain models for use in animations as has been the case hitherto. The writers’ second contribution (1) enhances realism in animations of several common construction operations; and (2) allows the visualization of several other construction processes that were hitherto impossible to animate accurately in 3D. [ABSTRACT FROM AUTHOR]

Multiresolution terrain models describe a topographic surface at various levels of resolution. Besides providing a data compression mechanism for dense topographic data, such models enable us to analyze and visualize surfaces at a variable resolution. This paper provides a critical survey of multiresolution terrain models. Formal definitions of hierarchical and pyramidal models are presented. Multiresolution models proposed in the literature (namely, surface quadtree, restricted quadtree, quaternary triangulation, ternary triangulation, adaptive hierarchical triangulation, hierarchical Delaunay triangulation, and Delaunay pyramid) are described and discussed within such frameworks. Construction algorithms for all such models are given, together with an analysis of their time and space complexities. [ABSTRACT FROM AUTHOR]