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In the summer of 2003, the US Department of Agriculture contracted for the acquisition of a new set of statewide aerial photography for Indiana. The new 1-meter, color images (3 band) were captured in mid-summer (leaf-on). The Natural Resources Conservation Service (NRCS), a component of the US Department of Agriculture, provided Indiana University with the 2003 NAIP data sets. The data set is comprised of two products: quarter quads and county mosaics.
The 2003 NAIP quarter quads are available in GeoTIFF and MrSID generation 3 (MG3) format. The MrSID format images are available as lossless and 20:1 compression ratio images.
Coordinate System: UTM, Zone 16 North
Horizontal Datum: NAD83
Pixel Resolution: 1 meter
Scale: 1:12,000
MrSID encoding ratio: 20:1
File size, GeoTIFF: approximately 110 MB each
File size, Lossless MrSID: approximately 60 MB each
File size, 20:1 MrSID: approximately 7 MB each
The 2003 NAIP County Mosaics are available in two formats: MrSID Generation 2 (MG2) and MrSID Generation 3 (MG3). The USDA provided the MG2 files. Each file includes the full extent of an Indiana county, but also includes some surrounding black (no data) areas.
Indiana University, Data Management Services, created the MG3 files by clipping the black (no data) areas out of the MG2 images. This was done to create a set of images for Indiana that could be seamlessly tiled without the overlapping no data areas. In order to completely remove the no-data areas, some counties were split into multiple files and some county files do not include the entire county extent. The MG3 files are somewhat smaller than the MG2 files because, having been clipped, they generally cover less area. Both MG2 and MG3 files have the same *.sid extension.
Each county image is archived in a .zip file which includes a MrSID image file (.sid), a MrSID world file (.swd), an ESRI .aux file (for projection information), a [countyname]_info.txt file which describes the encoding process, a list of images mosaiced, coordinate information and other metadata information, and a [countyname].txt file with FGDC metadata information. The FGDC metadata includes source date for each quarter-quad image included in the county mosaic.
Coordinate System: UTM, Zone 16 North
Horizontal Datum: NAD83
Pixel Resolution: 1 meter
Scale: 1:12,000
Target encoding ratio: 50:1
Actual encoding ratio: ~60:1
MG2 mosaic file size range: 50-150 MB each
Total archive size: 10 GB
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