Forcing GAMAP to Read datainfo.dat and tracerinfo.dat

Occasionally, odd errors will occur when processing data with some IDL routines which are caused by a non-matching datainfo.dat or tracerinfo.dat file. Standard versions of these files are stored in the GAMAP2 directory and are used to provide information on tracers and other data created by GEOS-Chem. These files (not the ones in the model directory) are used by GAMAP and related routines. These errors can usually be mitigated by forcing GAMAP to read the files in the model directory. The following is taken directly from the online GAMAP wiki (


User A said he keeps getting this message:

% UPDATE_TRACER_DATAINFO: WARNING: Use_DataInfo appears independent from global array!

User B said:

My ctm.bpch files have duplicate data blocks for some parameters. Something's wrong!


These are symptoms of diaginfo.dat or/and tracerinfo.dat that do not match the binary punch file (user B), or that the bpch file was created with inadequate diag/tracerinfo.dat files and end up with duplicate 999 tracers without tracername for example (user B). The solution is to use correct diag/tracerinfo.dat when reading and creating bpch files. GEOS-Chem now writes those files for each runs in your run directory. If you use them when reading run outputs, you will not have a problem.

The first time a GAMAP routine is used, it will look for and read these files. First, in the current directory, then in the !path variable (which means it will used the default ones in ../gamap2/input_files/). So, to read those corresponding to your run you can:

  1. start your IDL session in your run directory
  2. start your IDL anywhere, and then: cd, 'your_run_directory', before using GAMAP
  3. copy your diag/tracerinfo.dat from your run dir to your ../gamap2/input_files/ (i.e., overwrite default ones), before using GAMAP
  4. Advanced users can also, at anytime in their session, force GAMAP to read specific diag/tracerinfo.dat:
ctm_diaginfo, /all, /force_reading, filename='your_diaginfo.dat'
ctm_tracerinfo, /all, /force_reading, filename='your_tracerinfo.dat'

If you are using a default location, double check that it is really used with the following query:

print, file_which('tracerinfo.dat')