FortranGIS project includes a collection of Fortran interfaces to some common Open Source GIS (Geographic Information System) software libraries, plus some more Fortran-specific tools.
The libraries interfaced at the moment are Shapelib, GDAL, Proj and ReadOSM.
Shapelib is a library for handling ESRI shapefiles, a very common vector file format in GIS. This Fortran interface covers the full Shapelib API, including reading and writing of all kinds of shapes and dbf attributes. All the procedures interfaced in Fortran are documented with Doxygen. The Fortran API for Shapelib is stable and unlikely to undergo any change.
GDAL is a library for the input/output of a number of georeferenced raster (gridded) data formats. Since release 2.0, this Fortran interface includes bindings to almost all the GDAL C functions, allowing read and write of any file format supported by GDAL. This incidentally allows to read in Fortran also common graphic formats such as jpeg, png and gif. For some common procedures, a Fortran-specific interface is available, thus simplifying the work for Fortran programmers. The Fortran-specific procedures are documented with Doxygen, while for the procedures directly interfaced to the native GDAL functions you should refer to the original GDAL C API documentation.
Proj is a library for handling a big number of geographical projections and coordinate conversions. The Fortran interface covers bith the deprecated proj.4 API (available as legacy bindings up to proj version 7) and the new proj version 6 API. The availability of each of the interfaces is detected automatically at configure time. In both cases the most common procedures of the proj library are interfaced and they are considered stable. Here as well a Fortran-specific interface is available for some procedures.
ReadOSM is a library for extracting data from Open Street Map .osm and .osm.pbf files which can be downloaded with various tools from the OpenStreetMap platform. It is still experimental and is not built by default.
The interfacing to the C APIs within this project is done through the ISO_C_BINDING Fortran2003 intrinsic module. This is supported nowadays by most commercial Fortran compilers as well as by the free gfortran compiler. Since version 2.3, FortranGIS makes use of some extra Fortran 2003 features besides bindings to C, thus gfortran version 4.6 or higher is recommended.