AN IMPLEMENTATION OF THE PROCEDURAL GENERATION OF UNSTRUCTURED QUADRANGULAR GRID ALGORITHM BASED ON A STRUCTURED TRIANGULAR GRID IN REGULAR HEXAGONS ON THE PLANE

Работа посвящена реализации алгоритма процедурной генерации нерегулярной четырехугольной сетки, позволяющего рассчитывать сетку для большой области в реальном времени. При генерации используются кубическая система координат, в которой строится регулярная треугольная сетка для каждой ячейки шестиугольной сетки, процедура релаксации четырехугольной сетки. This work is devoted to the implementation of an algorithm for procedural generation of an unstructured quadrangular grid, which allows to calculate the grid for a large area in real time. When building the grid, a cubic coordinate system, in which a structured triangular grid is built for each cell of a hexagonal grid, and a relaxation of the quadrangular grid algorithm are used.

Multi-UAV Coverage Path Planning Based on Hexagonal Grid Decomposition in Maritime Search and Rescue

In the event of a maritime accident, surveying the maximum area efficiently in the least amount of time is crucial for rescuing survivors. Increasingly, unmanned aerial vehicles (UAVs) are being used in search and rescue operations. This study proposes a method to generate a search path that covers all generated nodes in the shortest amount of time with multiple heterogeneous UAVs. The proposed model, which is a mixed-integer linear programming (MILP) model based on a hexagonal grid-based decomposition method, was verified through a simulation analysis based on the performance of an actual UAV. This study presents both the optimization technique’s calculation time as a function of the search area size and the various UAV routes derived as the search area grows. The results of this study can have wide-ranging applications for emergency search and rescue operations.

Analysis of securing territories with states of the state geodesic network

The purpose of the work is to investigate the possibilities of using geospatial analysis to assess the state of geodetic support of territories for mapping of different scales, on the example of Ivano-Frankivsk region. Method. Methods of geospatial analysis, in particular zoning of the territory by means of buffer polygons, and also application of a hexagonal grid are used for researches. Results. An algorithm for estimating the state of geodetic support of territories using the method of buffer zones and the method of hexagonal polygons is presented. A comparison of methods is performed and graphical schemes of both methods are presented. The analysis of the results allowed to establish that the state of geodetic support of the territories of the studied areas varies widely. For mapping on a scale of 1:10000 and 1:25000, geodetic support varies between 65–92 %, depending on the area. Bogorodchany district has the highest indicators, Horodenkivsky district has the lowest. The percentage of territories is reduced for larger scales of 1:5000 and 1:2000. Mapping on such a scale requires additional network thickening. The method of hexagonal polygons on average showed better results by 6.4 % than the method of buffer zones. The maximum difference between the calculated collateral obtained from the two methods is 9.7 %; the minimum is 2.4%. Scientific novelty and practical significance. The analysis of the provision of SGN points using geospatial analysis, on the example of Ivano-Frankivsk region, showed the feasibility of its use for these purposes. A comparative analysis of geospatial analysis methods to assess the state of geodetic support based on graphical materials and quantitative characteristics showed that the best results can be obtained using the method of hexagonal polygons. Using the method of buffer zones gives less reliable results. The proposed and researched approach can be used to study the provision of points of the State Geodetic Network for the whole territory of Ukraine, as well as for the territories of individual OTGs, districts and regions.

Efficient Pathway Identification from Geospatial Trajectories

<p>In the earth-physics community Lagrangian trajectories are used within multiple contexts – analyzing the spreading of pollutants in the air or studying the connectivity between two ocean regions of interest. Huge amounts of data are generated reporting the geo position and other variables e.g. temperature, depth or salinity for particles spreading in the ocean. As state-of-the-art, these experiments are analyzed and visualized by binning the particle positions to pre-defined rectangular boxes. For each box a particle density is computed which then yields a probability map to visualize major pathways. Identifying the main pathways directly still remains a challenge when huge amounts of particles and variables are involved.</p><p>We propose a novel method that focuses on linking the net fluctuation of particles between adaptable hexagonal grid cells. For very small areas the rectangular boxing does not imply big differences in area or shape, though when gridding larger areas it introduces rather large distortions. Using hexagons instead provides multiple advantages, such as constant distances between the centers of neighboring boxes or more possibilities of movement due to 6 edges instead of 4 with a lower number of neighbors at the same time (6 instead of 9). The net fluctuation can be viewed as transition strength between the cells.Through this network perspective, the density of the transition strength can be visualized clearly. The main pathways are the transitions with the highest net fluctuation. Thus, simple statistical filtering can be used to reveal the main pathways. The combination of network analysis and adaptable hexagonal grid cells yields a surprisingly time and resource efficient way to identify main pathways.</p>

Modelling of ecosystem services “cooling effect” supply in the city of Тyumen

This article aims to identify the main factors influencing the supply of the “Cooling Effect” ecosystem service, which is important for creating a comfortable urban environment. The parameters of the ecosystem service “Cooling effect” (supply and demand) are expressed quantitatively as the difference between the surface temperatures and the maximum comfort temperature for the summer period (23°C) for the mathematical regression model of the process. The results of field observations and analysis of space images allowed us to verify the cartographic basis of the Open Street Map and organize thematic data for modeling: we sorted natural objects by area (selected with an area of at least 1 hectare), buildings by the criterion of multi-story, roads by the criterion of the number of lanes. To determine the dependence of temperatures on the selected indicators, the urban area was covered with a hexagonal grid with a hexagon radius of 500 m. The cells (bins) of the constructed hexagonal grid were selected as the operational research units. Areas are calculated as a percentage within the bin, distances—as the nearest in meters from the bin to the specified objects in a straight line. Calculations were performed in ArcGIS Pro software using tools from the Spatial Statistics—Spatial Relationship Modeling toolbox. The model building algorithm includes sequential launch of two analysis tools: Exploratory Regression and Ordinary Least Squares (OLS). Based on the results of the work of the tools, the following were performed: interpretation and analysis of reports, messages and maps. As a result of the study, the main factors influencing the temperature distribution have been identified. The strongest variables are the area of multi-storey buildings and the distance to major roads. The third most important factor is the forest area.