Nov 2011 DVC Geog 160 Introduction to Remote Sensing Internet sites for downloading remote sensing data NASA Landsat & SRTM DEM site (plus other images & maps) http://glcf.umiacs.umd.edu/index.shtml USGS Landsat Site http://glovis.usgs.gov/ USGS Remote Sensing (includes aerial photography) Site http://edcsns17.cr.usgs.gov/EarthExplorer/ ASTER DEMs (30 meter grid) – you need a log-in for the Global Data Explorer https://lpdaac.usgs.gov/content/view/full/11033 (info)

ASTER GDEM tiles are available through the REVERB, Global Data Explorer, and ERSDAC GDS search and order interfaces.

Global Data Explorer: http://demex.cr.usgs.gov/DEMEX/

GIS Data Depot (some data types cost $$ - you set up an account) http://data.geocomm.com/ California GeoSpatial Clearinghouse (Cal-Atlas) http://atlas.ca.gov/ Numerous websites for digital GIS data (including San Francisco Bay Area) http://www-sul.stanford.edu/depts/gis/web.html DigitalGlobe Quickbird & Worldview Demo imagery http://www.digitalglobe.com/index.php/70/Product+Samples GeoEYE IKONOS & GeoEYE Demo imagery http://www.geoeye.com/CorpSite/resource/sample_imagery.aspx Contra Costa County 2008 OrthoPhotographs & LiDAR .las data ftp://coco-county.projects.atlas.ca.gov/pub/coco-county/

STEPS to build a Layer Stack of downloaded Landsat or ASTER 1) Most often the individual bands are downloaded from a site as separate .tif grayscale images. The bands are zipped with some readme file and other information. 2) You have to stack the individual bands into a single, multi-band file so you can do multispectral image processing. This is termed “Layer Stacking” – all the bands will have the same spatial resolution after stacking (ERDAS chooses the smallest pixel size). You don’t stack the high-resolution panchromatic band with the color bands. 3) Here’s the workflow for a download of free Landsat TM data (6 – 30 meter VNIR-SWIR color bands and 1 – 120 m thermal band)

Figure 1. Typical stack of individual grayscale bands

Figure 2. Hold down “Ctrl” key and highlight bands you want to load into one view

Figure 3. 7 bands separately loaded into one view

Figure 4. Layer Stack task

Figure 5. Select bands that you want to stack into one file

Figure 6. Here’s the 7 bands selected for stacking into one multispectral file

Figure 7. Multispectral Landsat TM file (right side) with 7 bands – ready for image processing!! DOWNLOAD DAILY MODIS IMAGES!! If you want to download a recent (within 2 hours!!??) MODIS image as a jpg, kmz, or large GeoTIFF, you go to this website. The calendar uses Julian dates – not months & days…so 0 is Jan. 1 and 365 is Dec. 31. http://lance.nasa.gov/imagery/rapid-response/subsets/ Choose… -a Geographic Area, -a Subset (FAS seems to work for me…), -either Terra or Aqua, -the type of image you want (natural color, enhanced color, other color, NDVI) -resolution (250 m pixels is as good as it gets), -The downloads can take some time as the 250 m