PreProcessing Techniques for SWReGAP Land Cover Analysis

1
Pre-Processing Techniques for SWReGAPLand Cover
Analysis
T. Scott Schrader New Mexico Cooperative Fish
Wildlife Research Unit New Mexico State
University, Las Cruces, NM

• Southwest Regional GAP Project
• Arizona, Colorado, Nevada, New Mexico, Utah

US-IALE 2004, Las Vegas, Nevada
Transdisciplinary Challenges in Landscape Ecology
2
Initial Technical Steps in Production of Land
Cover Data

• ETM Characteristics and MRLC
• Atmospheric Standardization Techniques
• Cloud/Shadow Elimination

3
LandSat 7 ETM

• Spatial Resolution 30m pixels, 172km2
• Spectral Resolution 6 bands
• Temporal Resolution Worldwide 16 days

4
MRLC

• Multi-Resolution Land Characteristics (MRLC)
  Consortium established 1992, revised 2001
• Consolidation of the acquisition of remote
  sensing data for multiple agency use
• EPA, USGS, NBS, BLM, NOAA, NASA, USFS, EROS

5
MRLC

• 3 Seasons Green up, leaf on, leaf off
• lt 15 cloud cover
• Geometric terrain correction
• NALPS format
• Standardized projection
• Instrument artifacts removed

6
Atmospheric Standardization

• What is it? Why is it needed?
• Tools for three methods of Standardization

7
Atmospheric Standardization Tools

8
Areas Contaminated by Clouds/ Shadows
9
Outline Cloud/Shadow Areas
10
Excise Contaminated Areas
11
Start labeling Cloud/Shadows
12
Labels Complete
13
Recode Cloud/Shadow
14
Clean Up Procedures

• Clump Mark pixels that are isolated
• Eliminate Replace isolated pixels with
  surrounding values
• Neiborhood Buffer areas slightly to include
  mixed pixels at edges

15
Clouds/Shadows Masked
16
Clouds/Shadows Removed
17
Summary

• ETM appropriate for regional land cover mapping
• Atmospheric standardization to reduce scene to
  scene variability
• Mask areas to provide the best possible canvas
  to characterize land cover

18
For More Information

• ETM http//ltpwww.gsfc.nasa.gov/IAS/handbook/han
  dbook_toc.html
• MRLC http//landcover.usgs.gov/

19
For More Information

• Standardization Tools http//www.gis.usu.edu/pro
  jects/swregap/
• ImageStandardization.htm
• SWReGAP http//fws-nmcfwru.nmsu.edu