Guide to Using DOQQs from the ARIA Site
Viewing Search Results
Once you've identified a DOQQ you want, click its radio button and then choose to either download the image, preview it or view the metadata. (see below)
If the Band is equal to "1", the image is Black & White
- If the Band is equal to "3", the image is in Color.
- Path refers to the longitude (e.g. -111, or W 111 degrees).
- Row refers to the latitude (e.g. 32, or N 32 degrees).
- Place Name refers to the topographic quadrangle and which quadrant it is in.
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Note the HUGE sizes of some files! (as high as 48 megabytes each) |
If you click on Preview, the image comes up on the screen.
If you click on Metadata, a screen will come up with information on Identification, Image, Time, Location, Processing, Projection, Original Source, Current Owner, Use Restrictions, Comments, and Creator of the Metadata.
If you click on Download, you'll be shown a box to input your e-mail address. Then you'll see a screen where you'll see what files you can download (*.tif and *.hdr). The file name, such as 33111f42.tif, refers to the topographic map that the file corresponds to and what quadrant it's in. The *.tif files are the image files you'll want to download and the *.hdr files include the metadata information. Follow the instructions on the screen. It may take a while to download. For instructions on how to use DOQQs with ArcGIS, click here.
Note: Most DOQQ image files are very large, anywhere from 3 to 50 MB in size. Make sure you have enough space on your computer to download the file and enough RAM (recommend 64MB mininum) to view it in the imaging software you use.