This data set contains reduced-resolution QuickBird imagery and geospatial data for the entire Barrow QuickBird image area 156.15Â° W - 157.07Â° W, 71.15Â° N - 71.41Â° N) and the Barrow B4 Quadrangle (156.29Â° W - 156.89Â° W, 71.25Â° N - 71.40Â° N), for use in Geographic Information Systems (GIS) and remote sensing software. The original QuickBird data sets were acquired by DigitialGlobe from 1 to ... 2 August 2002, and consist of orthorectified satellite imagery. Federal Geographic Data Committee (FGDC)-compliant metadata for all value-added data sets are provided in text, HTML, and XML formats. Accessory layers include: 1:250,000- and 1:63,360-scale USGS Digital Raster Graphic (DRG) mosaic images (GeoTIFF format); 1:250,000- and 1:63,360-scale USGS quadrangle index maps (ESRI Shapefile format); an index map for the 62 QuickBird tiles (ESRI Shapefile format); and a simple polygon layer of the extent of the Barrow QuickBird image area and the Barrow B4 quadrangle area (ESRI Shapefile format). The baseline geospatial data support education, outreach, and multi-disciplinary research of environmental change in Barrow, which is an area of focused scientific interest. Data are available either via FTP or on CD-ROM.
Quality checks were performed throughout all processing procedures. Z-profiles for multispectral tiles were viewed for various locations in the image. Vegetation, water features and human-made features were checked for correct radiometric values. Actual digital number (DN) values were checked for individual tiles and for corresponding areas in the mosaics. Pixel registration of pan and ... multispectral tiles were checked. The Barrow orthoimagery location accuracy is defined as custom; the investigator team supplied the digital elevation model (DEM) and ground control points (GCPs). Imagery meets and usually exceeds QuickBird's specifications for 1:12,000 scale orthoimagery, which is defined as 10.2 meters CE90% and 6.2 meters root-mean-square error. Radiometric, sensor, and geometric corrections were applied to separate images by DigitalGlobe and images were mapped to a cartographic projection using a digital elevation model (DEM) to correct parallax error due to l ocal topographic relief. Each image has a different location accuracy. See the PDF files 'Barrow QuickBird Quality Assessment Report.pdf' (distributed with the data) for GCPs used to geocorrect imagery, correction errors, and other issues related to quality control.