... but there is free open source software for resolving the problems that you all are having.    The software can be found at GDAL.org

 Why do I hesitate to bring this up?   Partly, because we have done a lot of work and spent a lot of money to be able to work with full county Mr Sid imagery directly within our crop recordkeeping software... and, being a prick, I struggle with making it easy to do the same thing for people using competitive products

But mostly, I hesitate because these tools are DOS commandline tools and they require the user to have some reasonable knowledge of projections and datums and image formats, etc.   I do not want to get put into a position of supporting the use of these tools because I recommend them.  (yes, there is a windows interface available, but trust me... you do not want to use it on Mr. SID Compressed County Mosaics).

With that said... this is an incredibly powerful set of software libraries for inclusion in other software packages, or utilities for stand-alone operation.   And it avoids writing a check to LizardTech (the developer of the Mr Sid format).   JPeg2000 is a format that is every bit as good as Mr Sid and is totally royalty free.   <StartSoapBox>It fries me that the USDA, because of the ESRI/LizardTech collusion chose to distribute imagery in a format that users must pay to use when a free and better format is available.</EndSoapBox>.

With this GDAL toolset, you can do things like:

• Transform Mr. SID imagery into .bmp, .jpg, .jp2, .img, etc, etc.
• Transform imagery from most any format into .jpg, .jp2, etc, w/o royalty (can't transform into Mr SID because that requires royalty).
• Reproject any image into a different coordinate system.
• Extract any rectangle (or polygon bounded area) from a large image into a small image (but you have to know the coordinates).
• Lighten/darken, etc, etc.

And... there is one feature that is especially useful if you deal with mutliple counties.   Because the USDA insists on using Mr Sid, they introduce a major problem in their images.  The images delivered are square, but if the county isn't, then part of the image will be "black"... they kind of clipped the actual imagery to the county border.    Most GIS engines can make one color (black or white, usually) transparent.  When one image is overlayed on another, the "black" areas become transparent and let the overlapping imagery from another file show through.   Well, the USDA uses a process that makes the black just be near black.   Individual pixels in this "black" area from from pure black to almost black to kind-of black, etc.   But, GIS engines can only assign a single color to transparent.  So the "almost" colors still display.   That means that only about 50% of the underlying imagery of the adjoining county shines through.   Here is an example.

Well, last spring, MapShots and Pioneer Hi-Bred funded an effort by the GDAL organization to add a "near black" function to their utilities.   This function will unzip a Mr Sid image, and transform anything that is black or near-black to black (as long as it is along the outside of an image... it doesn't touch legitimate black areas w/in an image).   After doing this, you can save it in a GOOD format (not Mr. Sid) and pretty much preserve the black area so that you can show two counties at the same time without the problem shown in the background.

Using these GDAL tools, we have reprocessed the Mr. SID imagery (most of it purchased, instead of downloaded free) into Jpeg2000 for about 15 states, and made it available to our customers to avoid the issues that are being discussed here.    With the Open Source GDAL toolset, any of the rest of you can do the same thing.

We are swamped with winter releases for our corporate clients, but I will make this commitment.   Sometime before the end of March, I will write a free utility that lets you display any size of Mr Sid imagery, draw a rectangle on it, and export the imagery in that rectangle (or field boundary) to JPeg2000 or any other non-SID imagery format of your choice.   I am loathe to see anyone drop a dime on the proprietary Mr. Sid format when there is a better solution available (JPeg 2000).   And I will help support anyone else that wants do do the same faster than I can get to it.  And I would be glad to support Carl or one or two others that might be willing to the full NAT community.  But I cannot support 437 imagery novices that are going to jump in and try to learn how to use the GDAL command line functions.   I really don't want to be a prick about it.  I hope you understand where I'm coming from.