Geographic Information System

A Geographic Information System (GIS) is a system for capturing, storing, analyzing, and displaying spatial data. It is the intersection of cartography, database management, and spatial analysis — a discipline that treats the Earth's surface as a computable substrate rather than as a static backdrop.

The history of GIS is the history of translating geographic reality into data structures. Early GIS systems like ArcInfo and GRASS were monolithic: they handled storage, analysis, and visualization in a single closed platform. The modern GIS ecosystem is fragmented by design, with PostGIS handling storage, QGIS handling visualization, Python libraries handling analysis, and web APIs handling distribution. This fragmentation is not a failure of integration; it is a success of composability. The GIS that tried to be everything has been replaced by the GIS that knows what it is not.

The foundational tension in GIS is between the Vector Data Model — points, lines, and polygons — and the Raster Data Model — grids of pixels. Each model makes a different ontological claim about what geography is. The vector model says geography is topology: a road is a line that connects two nodes. The raster model says geography is continuous field: elevation is a value at every coordinate. Neither model is wrong. Neither model is complete. The GIS that pretends to one model is the GIS that blinds itself to the other.