proj-fortran

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PROJ is a generic coordinate transformation software, that transforms coordinates from one coordinate reference system (CRS) to another. This includes cartographic projections as well as geodetic transformations.

This repo contains a C-Binding for Fortran of the C PROJ library.

Dependences:

• C-PROJ Library (version > 6.0)

Commands:

• call proj_trans( srs_in, srs_out, x, y)

How to use it:

Just call the library with the use proj statement on your Fortran code:

program test_program
   use proj
   implicit none

   integer, parameter :: np = 4
   real(8), dimension(np) :: lats, lons
   character (len=*), parameter :: lcc_proj_example="+proj=lcc  +lon_0=-90 +lat_1=33 +lat_2=45"
   character (len=*), parameter ::     lonlat_proj4="EPSG:4326" !"+proj=longlat +ellps=WGS84 +datum=WGS84 +no_defs" 
  
   !! corners of EU meteo in projected lon-lat
   lons(1:np) = [ -26.,-26. , 40. , 40. ]
   lats(1:np) = [ -35., 22.5, 22.5,-35. ]
  
   print '("Original coordinates: ",4(F12.3))',lons,lats
   call proj_trans( lonlat_proj4   , lcc_proj_example, lons, lats)! forwards
   print '("After transformation: ", 4(F12.3))',lons,lats

end program

When compile, do not forget to add the -lproj flag, for example:

user@pc:~$ gfortran -c -O2 -ffree-line-length-none -w  -I/usr/include proj.f90 -o proj.o
user@pc:~$ gfortran -c -O2 -ffree-line-length-none -w  -I/usr/include test.f90 -o test.o
user@pc:~$ gfortran -O2 proj.o test.o -lproj  -o a.out

To do list:

• Show how to compile PROJ from source
• If necesary look for another usefull commands.