Learning Geospatial Analysis with Python - Second Edition

Elevation data

A Digital Elevation Model (DEM) is a three-dimensional representation of a planet's terrain. In the context of this book, this planet is the Earth. The history of digital elevation models is far less complicated than remotely-sensed imagery but no less significant. Before computers, representations of elevation data were limited to topographic maps created through traditional land surveys. Technology existed to create three-dimensional models from stereoscopic images or physical models from materials such as clay or wood, but these approaches were not widely used for geography.

The concept of digital elevation models began in 1986 when the French space agency, Centre national d'études spatiales (CNES), launched its SPOT-1 satellite, ...