PROJ4

This page explains what is PROJ4 library and how to use it, both from command line and from a Fortran program.

PROJ4 is a Cartographic Projections library originally written by Gerald Evenden then of the USGS. This library has almost all projection types. Being written in C, a Fortran wrapper was developed as part of the GLIMMER project and can be found in libfproj4-1.0.tar.gz.

PROJ4

Installation

Windows

• Download http://download.osgeo.org/proj/proj446_win32_bin.zip
• Extract and copy "proj" folder to C:\
• Right-click "My Computer" and select "Properties"
• Select "Advanced" tab
• Select "Environment Variables"
• In the "System Variables" box select "Path" and click "Edit".
• At the end of the line, add "C:\proj\bin" and click "OK".
• In the "System Variables" box, click "New".
• "Variable Name" is PROJ_LIB and "Variable Value" is "C:\proj\nad".
• Click OK to close windows.

Now test it:

• Windows/Run/cmd
• cd .. until prompt is C:\>
• write "proj -V" to see the version of the library.

Linux

• Go to your Package Manager or download source code from http://trac.osgeo.org/proj/ and follow the instructions.

libfproj4 (Fortran Wrapper)

Compilation

UNIX

• extract libfproj4.tar.gz to some place (e.g. DIR)
• cd $DIR
• export export CC=icc
• export CFLAGS=-Bstatic
• export FC=ifort
• export FCFLAGS=-Bstatic
• ./configure --prefix=$DIR/libfproj4 --with-proj4=/usr/lib64 2>&1 | tee configure.mylog

• make 2>&1 | tee make.log
• make check 2>&1 | tee check.log
• make install 2>&1 | tee install.log

Windows

• Download \\kepler\Software\PROJ4\libfproj4.lib for Compaq Visual Studio, or
• Compile W32 static lib:
  1. Extract proj4 source code and configure it (bash configure).
  2. New project W32 static lib
  3. Add fort-proj.c (from libfproj4-1.0.tar.gz) and all *.c files (from proj4 source), except all that have main function : css2css, geod, nad2bin, nad2nad, proj.c.
  4. Project Settings / C/C++ / General / Preprocessor definitions : VISUAL_CPLUSPLUS ou IFORT
  5. Project Settings / C/C++ / Preprocessor / include : whatever\proj-4.6.0\src (the folder that has projects.h, because of directives #include <projects.h>)

Usage

UNIX

• pgf95 -g -o libfproj4_teste.exe libfproj4_teste.f90 /home/jjdd/Downloads/libfproj4-1.0/libfproj4.a -lproj -lm

Windows

• Files needed: libfproj4.lib, proj4.inc, proj4.f90, test-proj.f90

1. New Fortran console application
2. add fortran files
3. project settings:
   1. Link / Input / Obj/library modules : libfproj4.lib
   2. Link / Input / Additional include path : path to libfproj4.lib and proj4.inc)

Ellipsoids

• List of ellipsoids in PROJ4: proj -le
• More popular:
  • International 1909 (Hayford) intl a=6378388.0m b=6356912m rf=297.
  • New International 1967 new_intl a=6378157.5m b=6356772m
  • WGS 84 WGS84 a=6378137.0m b=6357002m rf=298.257223563
  • Normal Sphere (r=6370997) sphere a=6370997.0m b=6370997m

b = a*(1-f) = a*(1-1/rf)

Portuguese Coordinate Systems in PROJ4

You might want to get the libraries containing the coordinate transformations with portuguese datum pre-configured here. Install the libs in the proj_lib folder, inside the FWTools folder. By the way, you may want to install FWTools first.

Here's the command line on how to convert from military portuguese to wgs84:

> cs2cs +init=pt:dlxhgmil +to +init=pt:etrs89 < coords_input.txt

Portuguese Military Coordinates (Hayford-Gauss Military System)

• Projection: Gauss-Kruger
• Ellipsoid: Hayford (internacional 1924): a=6378.388Km, b=6356.912 Km
• Datum : Lisbon (Castelo S.Jorge: 38º42’43.631’’N, 9º07’54.862’'W, 111.229m)
• Central Point: 39º40’N, 8º07’54.862’’W
• Origin: -200Km horizontally and -300 Km vertically
• Usage:
  • +init=epsg:20790 <=> +proj=tmerc +lat_0=39.66666666666666 +lon_0=-8.131906111111112 +k=1.000000

+x_0=200000 +y_0=300000 +ellps=intl +pm=lisbon +units=m +no_defs no_defs <>

• • +init=esri:102164 <=> +proj=tmerc +lat_0=39.666666667 +lon_0=-8.131906111 +k=1.000000

+x_0=200000.000 +y_0=300000.000 +ellps=intl +units=m (no reference to Lisbon Datum!!)

Universal Transverse Mercator (zone 29N)

• Usage:
  • ModuleHorizontalGrid: +init=esri:32629 <=> +proj=utm +zone=29 +ellps=WGS84 +datum=WGS84 +units=m

External Links

• PROJ4
• libfproj4-1.0.tar.gz.
• Sistemas Referencia Portugueses
• PROJ4_HandlingCoordinateSystems.pdf
• Projections and Projected Coordinate System Formulas