DOQQ 1998 Frequently Asked Questions Monday, April 4, 2005
What is a DOQQ?

The answer to this question and other fundamental questions about DOQQs can be found on the DOQQ help page.

   

When will the entire state be covered?

-and-
What areas of the state are covered?
The entire state is covered as of December 16, 2001!
   
Why are the DOQQs stored in the MrSid format? The MrSid format allows for the DOQQs to be compressed greatly without sacrificing the visual quality of the image. A 150 megabyte DOQQ can be compressed using 50 to 1 compression into a 3 megabyte MrSid file. To the naked eye, there is very little change between the original image and the MrSid image.
   
What programs can I use to view the MrSid files?

There are several ways to view a MrSid image. One way is to use a GIS such as Intergraph Geomedia or ESRI Arcview that has native MrSid support.

A second way is to download a MrSid plugin for a program that you are using. Lizardtech, the maker of MrSid, has plugins for Autodesk AutoCAD, Bentley MicroStation, Adobe Photoshop, and others. Visit the Lizardtech site at http://www.lizardtech.com for more information.

The third way is to use the MrSid standalone viewer. This free viewer is downloadable from Atlas. Click here to download from Atlas the standalone viewer for Windows. For viewers for other operating systems and for more advanced viewing tools for MrSid images, visit the Lizardtech site at http://www.lizardtech.com.

   
How can I convert a MrSid file into a TIFF file? Download the MrSid viewer from Lizard Tech. The viewer has a function to write (export) a MrSid file to a TIFF file.
   
I need a large number of DOQQs, and downloading the files will take forever! How I can get a CD with the DOQQs that I need? We are able to ship the 1998 DOQQs on DVDs for a fee. For more information, see our ordering page.
   
How can I get the unrectified imagery? The unrectified imagery can be ordered from the NASA Regional Application Center at the University of Louisiana at Lafayette. Contact Brent Yantis at yantisb@rac.usl.edu for more information.
   
Will decompressing the MrSid file into a TIF file remove the loss from compression? No, the loss has already occurred. Again, in most cases, the loss is not noticable to the naked eye. Only those people interested in performing detailed data analysis should need the uncompressed files.
   
When will the DOQQs be updated? The 2004 DOQQ images are available on Atlas through the DOQQ 2004 Downloader.