TdhZones reports location relative to defined polygons (geofencing) using coordinates obtained from the device on which the app is running. Polygons used by TdhZones are defined within an sqlite database that may be created, viewed and edited using the TdhGIS personal computer software. Coordinates used by the polygons may be longitude/latitude or any coordinates that can be obtained by converting from long/lat data using the Proj4 library.
A typical use of TdhZones would be determining the name of the state where the device is located or is nearest to.
This client version relies on the free server program to access the geo database and perform the spatial analysis.