One-meter MrSid 2005 NAIP photos for Oregon
Here are the 2005 USDA NAIP photos for Oregon.
Main data page
Many of the files are > 2 gigabytes. They are posted in gigabyte pieces
that you need to re-assemble.
More on file formats
The MrSID .sid format is lizardtech's proprietary implementation of
wavelet compression. The compression ratio is about 15:1in this case,
with some loss of information. That's still very big.
MrSID files can be read in ArcMap and with Viewers and 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 mosaic.
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
Viewer. See an example (with
than 2 gigabytes cannot be downloaded under most systems, so they are
broken into gigabyte chunks.
Examine it, as it is always wise to
examine a program that a stranger asks you to execute on your computer.
To download, for example, Clallam County, type
This should download the 3 pieces and append them on the fly.
It may fail because the command line cannot find httpcat1.py. Either it should
in your searchpath or its full or relative location should be specified. It mayfail because your version of python does not contain urllib. Update. It may fail
because python is not in your searchpath. Either add it to your path or give
the path to python, e.g.
If you download these pieces you must append them with, e.g.:
- At the DOS prompt: copy/b
- unix prompt: cat fname.a fname.b
fname.c > fname
- Anywhere you run python: cat.py
where fname is, for example naip_1-1_1n_s_wa001_2006_1
Warning: I tested the DOS copy through a remote mount to my linux web server, and the process beat the server to a pulp. Web requests were failing and packets were dropping right and left. I was convinced I was suffering a hardware failure. No, it was just DOS.
This site is still under construction, but comments are welcome.
Webmaster: Harvey Greenberg