The MrSid format consists of highly compressed imagery in a proprietary format. It may be an orphan at this point, since it has been quite some time since I have seen any data in this format. This format might be losing the battle of the proprietary formats, which would be a nice victory for open formats.
This has not be tested recently; use carefully, and report any problems.
For direct viewing in MICRODEM, download
Unzip the two programs and place in c:\microdem\mrsid. Rename, if needed, to:
The most recent version appears to get serious about projections and needs a set of libraries and definitions.
When you do this, you can do the following:
|After opening a preview image, there will be a "MrSid" button on the map toolbar, to open higher resolution imagery. These can be huge, so do not get greedy with the area you request.|
MICRODEM extracts MrSid imagery to Geotiff with a world file, and stores it in the Windows Temp directory. It will be deleted when the program closes To save these Geotiffs, use the File, Save satellite image menu option.
|Set the maximum size of the Geotiff images to extract, in pixels, on the Imagery tab of the options form. The default is 2400, which will open a Geotiff no bigger than 2400x2400 pixels, which will be about 20 MB in size as a geotiff (4 MB each in 3 bands). If you had a MrSid that was 50,000 by 40,000 pixels, it would require 6 GB to extract at full resolution as a Geotiff, would take a very long time, and might well not display in MICRODEM.|
MrSid imagery does not has full registration (projection and datum) attached, and there is no standard way of getting it. The world file is incomplete, and the ESRI AUX file that many sites have available is an undocumented binary file. You will have to enter the data, which you can get either by downloading a metadata file to go with your MrSID images, or by carefully reading the web page where you get the imagery.
If you get historical scanned map in MrSid format, you need to extract the image at the resolution and subset level you want. Then save the image as a JPEG or PNG file, and register it.
Last revision 1/11/2018