A Geographical Information System, or GIS, is a system that stores, presents, and allows manipulation of spatial or geographic data. GIS applications are built on databases and contain a rich graphical user interface that manipulates multiple layers of geographic data in vector and raster formats.
GIS existed way before the Web was born. The first desktop GIS product was MapInfo Pro, released in 1986. One of the most popular products is ArcGIS, by Esri, the company that created the popular Shapefile format (.SHP), which is a de facto standard in the field. Free and open-source solutions include PostGIS (based on the Postgres database and used by many GIS applications), GRASS GIS and QGIS, which runs in Mac, Windows and Linux. They all support the Shapefile format as well as open web standards like GeoJSON and TopoJSON. GIS applications are also...