Microdocs: Ground truthing in the Bahamas

A project at Stanford University creates microdocs (micro-documentaries) on topics dealing with coral reefs, including a video on "ground truthing," which the site describes this way:

Satellites reveal many objects on the Earth’s exterior from their vantage point in space, but until recently they’ve never been able to accurately detail what is BENEATH the surface of the ocean. In this film, a team of scientists ‘ground truth’ an innovative use of satellite imagery to produce a new and groundbreaking research tool.

Researchers compare estimates of coral cover calculated from satellite images to what is actually present in the environment. Verifying this satellite image data makes this research tool, and any conclusions drawn from it, much more robust.