Brute-force orthorectification using OSSIM. Unlike OSSIM's ubiquitous application ossim-chipper --op ortho, this application will perform a map->world->image projection for every output pixel using bilinear interpolation resampling. The ossim-chipper app performs a dynamic grid interpolation to reduce the number of expensive projections performed and thus greatly speed up orthorectification. This implementation is dog-slow, but extremely simple. For example, in a single test case of a 3 GB panchromatic image, ossim-chipper completed orthorectification in just under 7 min, while orthoism took 3.4 hours. Simplicity has its costs.
Define an environment variable, OSSIM_INSTALL_PREFIX, pointing to the install directory that will contain OSSIM. This can be simply /usr but you'll need root priveledges when doing the make install.
Fetch OSSIM and build the ossim library as explained in the readme. Make sure to perform a make install before proceeding.
Check the ossim build by running ossim-info (assuming your executable path is set correctly).
Then build orthoism application:
> cd orthoism
> mkdir build
> cd build
> cmake ..
> make
Alternatively you can import the directory into CLion or other IDE and build from there, assuming it knows how to read cmake files.