Digital Imagery

Purpose

Explain how remotely sensed images store measurements as grids of pixels and why those measurements need context before they can be interpreted.

Outline

• Pixels, grids, and image metadata
• Digital numbers, calibrated values, and physical meaning
• Scene footprints, nodata areas, and valid observations
• Image collections and repeated observations
• Common sources of distortion, noise, and uncertainty

Later Examples

• Inspecting pixel values across a small image subset
• Comparing raw-looking imagery with calibrated reflectance
• Identifying valid and invalid pixels in a scene