|
Index to Digital Aerial Photographs |
What this map layer shows:
The positions of the Digital Orthophoto Quadrangles available.
|
|
Background Information |
Sample Map
The U.S. Geological Survey (USGS) produces digital aerial photographs, known as Digital Orthophoto Quadrangles (DOQ), that cover 3.75 minutes of latitude by 3.75 minutes of longitude. These photographs are orthorectified, which means they have been altered to correct geometric distortions, and they therefore present accurate measures of distance and direction. Four DOQs can be combined to cover the area represented by a standard USGS 7.5-minute, 1:24,000-scale topographic map. Because they are positionally accurate and show exactly what an area looked like at a specific instant, DOQs are useful for a wide variety of national, regional, and local applications, including land and timber management, routing and habitat analysis, environmental impact assessment, evacuation planning, flood analysis, soil erosion assessment, facility management, and ground-water and watershed analysis. Detailed information about DOQs can be found on the USGS Digital Orthophoto Program page, and the USGS Digital Backyard has further information on aerial photographs and other digital cartographic products.
The Index to Digital Aerial Photographs map layer shows the positions of the DOQs available for the United States, Puerto Rico, and the U.S. Virgin Islands. Descriptive information includes the DOQ name and a link to the Terraserver, where the photograph can be viewed.
|
|
|
|
|
|
|
|