1. Filling in the gaps in Landsat 7 data Northwest GIS Users Group Conference Boise, Idaho, October 19 – 21, 2011 William J. Kramber Idaho Department of Water Resources Boise, Idaho Dr. Richard G. Allen and Dr. Ricardo Trezza Kimberly Research Center, University of Idaho Kimberly, Idaho

2. Landsat  USGS/NASA mission  L5 launched 1984  L7 launched 1999 (damaged May, 2003)  30 meter pixels  16 day cycle  100 by 100 miles  Free  Landsat 8 will launch in December 2012  Landsat 9? NASA Landsat 7

3. p40r30_l7_20110728.img

4. Gaps in Landsat 7   Scan line corrector failed on May 31, 2003

5. Procedures   Reproject Landsat 7 image to IDTM83   Produce NDVI   Change gaps to unique value   Compute mean NDVI of CLU polygons   Fill in gaps with mean NDVI

6. Produce NDVI Normalized Difference Vegetation Index   ArcInfo tool developed by Eric Rafn   Converts Landsat bands 3 and 4 to reflectance   Outputs NDVI image   (IR – Red) / (IR + Red)   sensitive to vegetation density

7. NDVI_toa.img

8. Change gaps to unique value

9. Compute mean NDVI of CLU polygons ArcInfo Zonal Statistics (ignore nodata, snap to input) Input Output

10. Fill in gaps with mean NDVI

11. Concern about Landsat’s future   Landsat 5 is 27 years old   Landsat 7 is 12 years old   Landsat 8 is scheduled for launch in Dec. of 2012   Funding for Landsat 9 is uncertain

12. Landsat used in Idaho since 1975   Water rights monitoring   Adjudication   Land use and land cover mapping   Conservation Reserve Enhancement Program   Mapping Evapotranspiration

13. More Information Filling gaps Chen,J., et al., 2011, A simple and effective method for filling gaps in Landsat ETM+ SLC-off images, Remote Sensing of Environment, v.115, no.4, p.1053-1064. Landsat http://landsat.gsfc.nasa.gov/about/ http://www.idwr.idaho.gov/geographicinfo/landsat/LandsatConcerns.htm NDVI http://earthobservatory.nasa.gov/Features/MeasuringVegetation/measuring_vegetat ion_1.php Common Land Unit (CLU) http://www.fsa.usda.gov/FSA/apfoapp?area=home&subject=prod&topic=clu

14. Landsat mosaic