This article applies to GeoExpress on Mac OS and Ubuntu
1. Download http://www.kyngchaos.com/files/software/frameworks/GDAL-MrSID_Plugin-1.11.4-1.dmg and follow the instructions in the readme.rtf file to enable MrSID in QGIS. You can download the SDK compatible with your OS here:
These instructions require admin privileges on your machine as they will make machine-wide changes.
1. Download the latest version of the DSDK for Linux from https://www.extensis.com/support/developers. For this article we will be using MrSID_DSDK-18.104.22.16803-rhel6.x86-64.gcc531.tar.gz. If your downloaded filename is different (i.e. a newer version), remember that name because we will have to substitute it into commands later on.
2. Extract the downloaded DSDK into /opt
sudo tar -zxvf MrSID_DSDK-22.214.171.12409-rhel6.x86-64.gcc531.tar.gz -C /opt
Building GDAL with MrSID driver
1. Make a "src" directory in the home directory.
2. Download the gdal sources from the Ubuntu repository. You will need to enable source repositories if you haven't already (open "Software and Updates" -> check Source Code).
sudo apt-get update
apt source gdal-bin
3. Now cd into the directory that apt source made for you, this may be slightly different as Ubuntu packages are frequently upgraded.
4. Run the configure script, telling it the location to which you extracted the DSDK.
./configure --with-mrsid=/opt/MrSID_DSDK-126.96.36.19909-rhel6.x86-64.gcc531/Raster_DSDK --with-mrsid_lidar=/opt/MrSID_DSDK-188.8.131.5209-rhel6.x86-64.gcc531/Lidar_DSDK --with-jp2mrsid=yes
5. Run make to build gdal. Optionally, add -j 8 to build on 8 threads which will make building much faster.
make -j 8
6. Run make install, which will install gdal binaries and libraries to /usr/local/bin and /usr/local/lib respectively.
sudo make install
7. Add gdal libraries, and LT DSDK libraries to your system-wide environment variable, LD_LIBRARY_PATH, by appending the following to /etc/environment:
Log out, and log back in for the environment changes to take effect.
Verify that gdal built successfully and has MrSID capabilities
1. gdalinfo --formats | grep -i sid
2. Launch QGIS and open any .sid file.