INSTALLING

4/2016                        General Installation 

                    Quick Directions for the Default Configuration
                    "Any color that you like as long as it's black"

Download source code from

       ftp://ftp.cpc.ncep.noaa.gov/wd51we/wgrib2/wgrib2.tgz
       http://www.ftp.cpc.ncep.noaa.gov/wd51we/wgrib2/wgrib2.tgz

Untar the compressed tarball

       gunzip wgrib2.tgz
       tar -xvf wgrib2.tar
       
       or if you have gnu tar:  tar -xzvf wgrib2.tgz

Go to the main directory (grib2)

       cd grib2

Define the C compiler that you will be using.  Note icc and pgc have been
found to be incompatible with the Jasper library and are not allowed.

       sh/bash:    export CC=gcc
       csh/tcsh:   setenv CC gcc

Compile the wgrib2 using gnu make

       linux:      make
       MacOS:      gmake
       Unix:       ???    ask system administrators

Try executing wgrib2

      wgrib2/wgrib2 -config

Copy wgrib2 to SOMEPLACE

      cygwin/linux/unix: cp wgrib2/wgrib2 SOMEPLACE


                          Not So Quick Directions
                          So you want some options


Edit the file "makefile" and select the desired options:

# netcdf3: write netcdf files with netcdf-3 library
# netcdf4: write netcdf files with netcdf-4 library
# regex: regular expression package used by (match,not), POSIX-2
# tigge: enable -tigge option for tigge names
# mysql: write to mysql files
# ipolates: fortran interpolation library
# udf: user defined functions
# openmp: multicore support using OpenMP
# proj4: use proj4 for geolocation
# wmo_validation: used for testing new templates
# fortran_api:  fortran api for callable wgrib2, requires a fortran 2003
#               feature, subroutines can allocated/deallocated arrays
# disable_timezone: some OS do not handle time zones in POSIX maner
#
# the flags are stored in wgrib2/config.h
#
# Warning do not set both USE_NETCDF3 and USE_NETCDF4 to one

These are the default options

USE_NETCDF3=1
USE_NETCDF4=0
USE_REGEX=1
USE_TIGGE=1
USE_MYSQL=0
USE_IPOLATES=1
USE_UDF=0
USE_OPENMP=1
USE_PROJ4=0
USE_WMO_VALIDATION=0
DISABLE_TIMEZONE=0
MAKE_FTN_API=1

USE_G2CLIB=0
USE_PNG=1
USE_JASPER=1

COMMENTS:

1) Do not set both USE_NETCDF3 and USE_NETCDF4 to one
2) Some options require a compatible fortran compiler (usually gfortran).
   You need to set the environment variable FC before running make

       sh/bash:    export FC=gfortran
       csh/tcsh:   setenv FC gfortran

3) On some machines, you will have to define the C compiler
   and C preprocessor.  On the NCEP's AIX, I have to define
   them by

	export CC=/usr/vacpp/bin/xlc_r
	export CPP=/usr/bin/cpp


                          Netcdf

The makefile is set up to use either netcdf v3 or netcdf v4.  Netcdf-4
makes wgrib2 much bigger, so don't install it unless you really have to.
The source code for netcdf-4 (and necessary hdf5) is also very big
and will have to be downloaded separately.  The makefile will
prompt you for the downloads.  You also have to set the fortran
compiler. See (2).

The netcdf-3 library is included with this distribution.  The library is
compiled in enable-C-only mode which is not be that useful for
fortran code.  Don't use try to link other codes to this library.

                              MYSQL

Install MySQL requires the appropriate headers and libraries to be installed.
The makefile may have to be modified to reflect the locations of the headers
and libraries.


                  IPOLATES, interpolation library

IPOLATES is the interpolation library used by the -new_grid options.
In order to use this library, you must have a f90/f95/f2003 fortran compiler
enabled.  See (2).  You will have to change the source code if you are 
not using g95, gfortran, openf95 or xlf.

                              USE_UDF

Set to zero in 99.999% of the times. 

                             USE_PROJ4

Wgrib2 can use Proj4 as its geolocation library.  The default geolocation 
library, gctpc, is faster.  Proj4 is most used to compare check the
results from gctpc.


                        USE_WMO_VALIDATION

Has been used for validation of proposed WMO extentions.

                       DISABLE_TIMEZONE

Set to zero if most cases.  For one non-POSIX system, the time zones
had to be disabled in order for a certain option to work correctly.


                             OpenMP

OpenMP allows wgrib2 to run faster by using threading the code and
running on multiple cores.  When you enable OpenMP, your C compiler must 
support OpenMP v3.0 or higher.  


                          MAKE_FTN_API

The MAKE_FTN_API builds the wgrib2 library and the C and fortran API.
This enables C and Fortran codes to call wgrib2 as a subroutine. This
also requires a fortran compiler.


                            USE_G2CLIB

The internal grib decoders are better than g2clib so there is
little reason to link in g2clib.  However, I've gotten complaints
that wgrib2 decoded this field incorrectly.  My reply is that g2clib
got the same results.


                              USE_PNG

If set to zero, the png library is not linked in and png-compressed
grib message cannot be read.  When was the last time you saw a
png-compressed grib message?  Must be set to one if g2clib is
linked int.

                            USE_JASPER

If set to zero, the jasper library used for encoding and decoding
jpeg2000 is not linked in.  Since jpeg2000-compressed files are
very common, USE_JASPER should be set to one.  The only exception
is when you are cross-compiling wgrib2.  Using autoconfig scripts
(Proj4, png, jasper) can be a challenge.  Of course, you would
have restrict yourself to simple, complex or ieee packed grib.


                     INSTALLING on Cygwin and Windows

The code including the IPOLATES option compiles in the cygwin development 
system.  You'll have to install extra packages such as the C, gfortran 
compilers and various scripting utilities. 

    Before you compile, you set the default compilers.

    export CC=gcc
    export FC=gfortran
    make

                        INSTALLING on FreeBSD

Set appropriate CC and FC environment variables and try make. wgrib2 v1.9.8
was compiled with clang and gfortran.


                        INSTALLING on Apple OS-X

See Grace Peng's blog.


                        INSTALLING on NCEP's AIX

Define default C, C preprocessor and fortran

   export CC=/usr/vacpp/bin/xlc_r
   export CPP=/usr/bin/cpp
   export FC=xlf_r
   gmake


			Static vs Dynamic Libraries

The various libraries can be created in both dynamic and static versions.  
I've tried to make the add-on libraries static.  

                           Testing Package

Yes it does exist.

                             Problems

Perfection?  Not here.