One-meter MrSid 2009 NAIP photos for Washington State

These data have just arrived!

Some of this info has not been updated and pages in subdirectories may be missing or underdevelopment.

Main data page
The image files are huge. Check the files sizes to make sure that your browser got the complete file. If you don't want to download big files, you can buy the DVD for $50/county.
Counties:
Adams
Asotin
Benton
Chelan*
Clallam
Clark
Columbia
Cowlitz
Douglas*
Ferry
Franklin
Garfield
Grant*
Grays Harbor
Island
Jefferson*
King
Kitsap
Kittitas*
Klickitat
Lewis
Lincoln
Mason
Okanogan* (two files)
Pacific
Pend Oreille
Pierce
San Juan
Skagit
Skamania
Snohomish
Spokane
Stevens*
Thurston
Wahkiakum
Walla Walla
Whatcom
Whitman
Yakima (two files)
 * Seven of the files are > 2 gigabytes. This can be troublesome. See Large Files below.

More on file formats

The MrSID .sid format is lizardtech's proprietary implementation of wavelet compression. The compression ratio is about 15:1 in this case, with some loss of information. That's still very big. MrSID files can be read in ArcMap and with Viewers and plugins (including browser plugins) from LizardTech. The .aux file is an optional auxillary file created by ArcMap. The .sdw file is a "world" file with the values to transform from row/column numbers to northing/easting. Most software does not need this. The .shp file, along with all the other files bearing the same root name, constitute a shapefile. This is an ESRI polygon format, readable by many other software packages. It shows the component quarter quads of the mosaick. Around here, a "quadrangle" is a 7.5-minute by 7.5-minute (~7 by 10 mile) area as seen on a USGS 1:24000-scale topo map. Hence a quarter quad is 3.75 minutes by 3.75 minutes.

MrSID files can be viewed, and subsets can be written to image files with the free TatukGIS Viewer. See an example (with world file).

Large Files

2147483647 is the largest value that can be expressed as a signed four-byte integer. When files get larger than this (2 gigabytes), things start getting weird. FAT filesystems (an old Windows format that you might still find on old systems, especially external drives) will fail. Internet explorer will stop exploring. Many programs (.e.g. Arc/INFO workstation) will complain about pointers out of range. (Ask your grandpa about the 32K limit.) However, I am happy as a clam at high tide with huge files while using Windows XP, firefox, and ArcMap.

Most of these files are under two gigabytes, but ten are larger. Thanks to our server updates (Thank you, Ed.), you can now download these huge files in one piece.

Webmaster: Harvey Greenberg