TdhGIS provides a robust and versatile set of tools for vector based spatial analysis. Everything needed to be performing spatial analysis within minutes is included in this easy to use software package.
Graphically create and edit geometric data, as with a CAD program
Import Shapefiles and OpenStreetMap data
Use raster images as background and a CAD drawing as an overlay
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 closest to each hospital)
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 Sqlite 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!