Flashcards

Hord (1982). The Bayesian variant of Max Likelihood lets you enter prior probabilities instead of assuming equal priors for all classes.

Simple Ratio (SR) = NIR / Red. Originally used by Jordan (1969); Cohen (1991) called it the first true vegetation index. NDVI (Rouse 1974) fixed SR’s unbounded range.

• 📅 Year: 1976
• 📋 Use: the standard hierarchical land-use / land-cover scheme for RS data
• 🌐 Structure
  • Level I — 9 classes
  • Level II — 37 subclasses

French/European Earth-observation series, run by CNES.

• ✅ Still active
  • SPOT 6 — launched Sep 2012
  • SPOT 7 — launched Sep 2014 (now operates as Azersky)
• 🪦 Retired
  • SPOT 1 — Feb 1986 → 1990
  • SPOT 2 — Jan 1990 → Jul 2009 (19-year run!)
  • SPOT 3 — Sep 1993 → Nov 1996 (failure)
  • SPOT 4 — Mar 1998 → Jun 2013
  • SPOT 5 — May 2002 → Mar 2015

⚠️ SPOT 1–3 have no blue band — important quirk on the older satellites.

Washington, D.C., late 1999 (shortly after the Sept 24, 1999 launch). A landmark — sub-meter civilian imagery had been restricted to defense until then.

1. Geo
2. Standard Ortho
3. Reference
4. Pro
5. Precision
6. PrecisionPlus

Sold by square kilometer.

Launch failure in 1993. Failed to reach orbit due to a propellant leak. First gap in Landsat continuity.

AVHRR imagery of the US Great Plains. The normalized-difference form kept values bounded (unlike SR) and reduced illumination variability — became the canonical VI.