April 10, 2015 -- TdhGIS now imports OpenStreetMap (OSM) data for Polygons, Multilines and Points based on user selected tags for Ways, Relationships and Nodes.
The available data in OSM is impressive and growing, covering large parts of the world. Now, TdhGIS can use this data for all manner of spatial analysis including area and perimeter calculations, polygon intersections and point to polygon allocation.
Using raster images as spatially referenced background, spatial analysis results can be displayed over relevant maps, drawings or photos.
TdhGIS databases can be used within the mobile device location app TdhZones, to identify location relative to user defined polygons (e.g. which service zone am I in?). TdhGIS (for MS Windows and Linux) and TdhZones (for Android) are totally free and can be downloaded at tdhgis.com.