Title: | Pond Area Estimates: Nine Study Regions in Alaska for 3 time periods (1950s, 1978-1982, 1999-2001) using remotely sensed images |
Contacts: |
McGuire, Anthony David Riordan, Brian Verbyla, Dave Verbyla, Dave |
Abstract: | The data are ArcGIS shapefiles by USGS quadrangle within 9 study regions: Arctic Coastal Plain, Stevens Village area, Yukon Flats, Minto Flats, Denali Flats, Talkeetna, Innoko Flats, Tetlin Flats, and Copper River Basin. Each shapefile polygon represents the shoreline of a pond as visually interpreted from each georectified remotely sensed image. All images were rectified based on at least 25 control points from 1:63 360 USGS digital raster graphics topographic maps using a second-order polynomial with a RMS error of less than one satellite image pixel (30 meters). All closed-basin ponds greater than 0.2 hectares were visually delineated and manually traced as polygons using ArcGIS. Each pond polygon has an ID and Hectares field representing the pond ID and area in hectares for the time period of the remotely sensed image. |
Methods: | The data were downloaded for the North America continent and then subset to the Alaska region. Maximum NDVI values for each year from 1May through 30 September were determined for each pixel using ArcGIS 9.2 Cell Statistics tool. The maximum annual NDVI values were then reprojected from the North American Albers projection to the the Alaska Albers NAD83 projection using nearest neighbor resampling with ArcGIS 9.2 project tool. Each NDVI values is scaled as Integer(NDVI*10000), thus a original NDVI floating point value of 0.5 is 5000 in the dataset. NDVI values can range from 0 to 10,000 in the dataset. |
Experimental Design: | 1950s for each study region using 1:40,000 scale panchromatic aerial photography acquired from USGS in Anchorage Alaska and then scanned at 600 dpi scanning density. Arctic Coastal Plain Region: 3Aug1999 Landsat ETM+, Tetlin flats Region: 4Aug1999 Landsat ETM+, Denali Flats, Yukon Flats, Stevens Village, Minto Flats, and Talkeetna Regions: 16Aug2000 Landsat ETM+, Innoko Flats Region: 18Aug2001, Copper River Basin: 7Aug2001 |
Supplemental Documentation: | None on file. |
Corrections: | None on file. |
Supplemental Acknowledgements: | None on file. |
Keywords: | primary production, remote sensing |
Categories: | Hydrology, Remote Sensing |
Study Period: | 1950-01-01 to 2001-08-18 |
Sampling Frequency: | Three time periods for each region: 1950s (panchromatic aerial photography), 1978-1982 (Color Infrared aerial photography), 1999-2001 Landsat ETM+ imagery |
Bounding Box: |
West Longitude: -180° |
Site References: |
Site ID: Alaska |
Data Columns: | |
Public Release: | 2008-12-10 |