1995-96 Digital Ortho Quarter Quads
Note - Because of the age and format of the DOQQs the software was unable to produce a complete mosaic dataset overview so it was decided to put a scale range on the DOQQs. The DOQQs will not be visible out beyond 1:250000. Even at that scale there will be what looks like gaps in the data. All the data is there, just zoom in closer.
Also, the quadrangle grid with annotation is included as reference.
Lastly, this service is technically a Map Service and not an Image Service, the reason being that the Quadrangle Grid is included.
DOQQS's were developed from aerial photography taken during the Winters of 1995 and 1996 under US Geological Survey's (USGS) National Aerial Photography Program (NAPP). The NAPP photographs consist of 9 x 9 inch film images scaled at 1:40,000 with each photo centered over one of the four quarters (NE,NW,SW,SE) of a USGS 7.5 minute (1:24,000) topographic map. Four individual NAPP photos are required to completely cover the area of a USGS 7.5 minute topographic map. To produce a DOQQ, the original 1:40,000 photography is reproduced as a 1:12,000 positive print which is scanned to produce a digital file with a ground resolution of 1 meter. These 1st order files are ortho-rectified and output as geotifs (over 150 MB each) referenced to UTM NAD83 coordinates. The MARIS staff has mosaiced and projected the geotif files, in sets of four, to create output files in MSTM coordinates that correspond to USGS 7.5 1:24,000 topographic maps. These composite files are compressed using MrSID compression software.