(runs on virtually any Linux or MS Win computer)
Downloads (no ads, no bots, no limits, no charge)
TdhGIS_linux for Linux
TdhGIS_win for MS Windows
Downloads last updated June 17, 2017

The purpose of TdhGIS is to perform spatial analysis of vector defined geometric data. This may include:
  • NEW=> graphically create and edit geometric data, similar to the abilities in a CAD program
  • Import OpenStreetMap data.
  • Use raster images as background for vector graphics.
  • Transform coordinates based on the Proj4 library.
  • Color polygons based on user data values using either Discrete intervals or Gradients.
  • Allocate point data to user specified buffers for points, polygons and multilines (e.g. find all gas stations within 1 mile of a highway).
  • Allocate point data to polygons. (e.g. assign structures to hydrological basins).
  • Allocate polygon data to other polygons. (e.g. allocate population data by census block to political boundaries).
  • Create thiessen polygons (e.g. for all hospitals within a state, define the areas where a particular hospital is closer than any other).
  • Create data contours (e.g. create lines of equal ground elevation based on a set of elevation points).
  • Create contour polygons (e.g. define the area where average rainfall exceeds a selected value based on weather station data).
  • Calculate the area and perimeter of irregular polygons, including exclusion polygons (i.e. holes).
  • Data is stored in an open database allowing manipulation by other software.
Even if you don't yet need these easy to use spatial analysis operations, TdhGIS makes a very good Shapefile viewer and editor!

About the author; Tim Hirrel (timhirrel@tdhgis.com)
If you like TdhGIS, please let me know. If you want changes, please let me know that, too. Writing software means never having to say you're finished. 

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TdhCad.com - Vector Graphics 
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TdhNet - Hydraulic Modeling for Water Distribution Systems