We describe several programs working with 1201x1201 gridded (array) terrain elevation data: determining the viewshed of an observer, and the visibility indices of all points, converting from a grid to a TIN, losslessly and lossily compressing a grid, and interpolating from contours to a grid. The intent is to integrate these, and new, programs, into a test suite the better to understand hypsogr...

We describe several programs working with 1201x1201 gridded (array) terrain elevation data: determining the viewshed of an observer, and the visibility indices of all points, converting from a grid to a TIN, losslessly and lossily compressing a grid, and interpolating from contours to a grid. The intent is to integrate these, and new, programs, into a test suite the better to understand hypsogr...

Solar Radiation is considered as an important parameter in modeling environmental, hydrologic and biophysical processes. One of the reasons that solar radiations are not extensively used in models is the problem of its measurement in different points. Solar Analyst Viewshed Algorithm makes possible calculation of the topographic effects on solar radiation at local and landscape scales. With res...

The analysis of social media content for the extraction of geospatial information and event-related knowledge has recently received substantial attention. In this article we present an approach that leverages the complementary nature of social multimedia content by utilizing heterogeneous sources of social media feeds to assess the impact area of a natural disaster. More specifically, we introd...

Visibility analysis or Viewshed is a common function of almost all GIS systems. The aim of this project is to find out the best solution, to compute viewshed for the Olomouc region and ensure the best way of visualisation of the results. The first step to analyze the visibility is making a high quality Digital Terrain Model, choice of the best interpolation method and subsequent addition of veg...

The knowledge of visibility information on a terrain is essential for a large number of current applications. There exist several algorithms in the literature for building visibility maps (VMs) but only for one single viewpoint or at most for a very small number of observers. This limitation is due to the high computational complexity of the used methods (which is greater than O(N2), where N is...