Geosheets is a tool that allows for both mapping and querying to be done directly within Google Sheets by adding a suite of custom geospatial functions
In the case of a semi-variogram, closer things have less variability and are similar. While things farther away are less predictable and are less related.
While not necessarily your prototype GIS package, GeoDa carries exciting analytical & visualization tools in industries like economics, health & real estate
Cartographers use lines to show the movement of phenomenon (people, ideas or money) in flow maps. To show the magnitude, they change the width of flow lines