TdhGIS - Vector Based Spatial Analysis

TdhGIS provides a comprehensive suite of vector based spatial analysis functionality*, imports OpenStreetMap data and Shapefiles, calibrates and displays raster images and provides CAD like editing of geo data. Data is stored in a fully documented sqlite database that can also be used in the mobile location app, TdhZones. TdhGIS runs on MS Windows and Linux, is totally free and can be downloaded at tdhgis.com. *Spatial Functions Include: Polygon areas and perimeters; Thiessen polygons; Centroids; Buffers; Contours lines and polygons; Polygon intersection, merge and subtraction; Allocation of data from points to polygons and polygons to polygons; Color polygons based on data values