Difference between revisions of "GAMAP tips and tricks"

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== Combining output from timeseries files ==
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On this page we list information about GAMAP, the Global Atmospheric Model Analysis Package. 
  
'''''Ray Nassar (ray@io.as.harvard.edu) wrote:'''''
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== Overview ==
  
:I just have a quick question, is there any GAMAP routine that can average all hourly data blocks in a timeseries file to make a single daily average bpch file? 
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GAMAP
  
:It appears like I could use the average option of ctm_sum.pro but I do not quite understand where the averaged data goes and afterwards would still have to write to bpch.
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* is a self-contained, consistent, and user-friendly software package for reading and visualizing output from chemical tracer models (CTM's)
 
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* consists of a suite of routines written in IDL (Interactive Data Language)
'''''Philippe Le Sager (plesager@seas.harvard.edu) replied:'''''
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* makes extensive use of IDL's powerful plotting features
 +
* can produce line plots, 2D plots, 2D animations, or 3D isocontour surface plots
 +
* can read 2D, 3D or 4D data blocks
 +
* can read output from the GEOS–Chem, GISS and FSU model families
 +
* can be easily customized to keep pace with ongoing model development
 +
* can be installed on any platform that supports IDL, thus ensuring a high degree of portability
 +
* can be coupled with the ION (IDL on the Net) interface to create interactive plots which can be served to a web page
 +
* can read data from ASCII, binary, netCDF (including COARDS conventions!), and HDF–EOS file formats
 +
* contains helper routines to read from / write to various file formats
  
:Check the
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The main GAMAP program contains a user-friendly, menu-driven interface; however, users may also call GAMAP subroutines independently of the main program. This makes it possible to embed GAMAP routines within existing IDL code.
  
/gamap2/timeseries/gc_combine_nd49.pro
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== Table of Contents ==
/gamap2/timeseries/gc_combine_nd48.pro
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:routines, which combines daily bpch files (nd48 & nd49 output, but also met field input files) into 4D data blocks. It has many options. You can extract a subset of data according to time and/or location, or process the data (moving average, daily max, shift to local time). You can either save the data into a new bpch file or just get an array of data in output.
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=== GAMAP web pages ===
  
:I wrote a tutorial that gives some pointers [http://www-as.harvard.edu/chemistry/trop/gamap/doc/timeseries_brief_tutorial.pdf here.]
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This page has now been split into several sub-pages:
  
:I notice that only gc_combine_nd48.pro has an option to get daily average. If you need that option for gc_combine_nd49.pro, let me know I can implement it.
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* [http://acmg.seas.harvard.edu/gamap/ GAMAP main page]
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* [http://acmg.seas.harvard.edu/gamap/doc/index.html GAMAP Online User's Guide]
  
:-Philippe
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=== GAMAP tips and tricks ===
  
--[[User:Bmy|Bmy]] 09:43, 1 April 2008 (EDT)
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* [[General GAMAP usage]]
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* [[File I/O with GAMAP]]
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* [[Color and graphics with GAMAP]]
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* [[Regridding with GAMAP]]
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* [[Date and time computations with GAMAP]]
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* [[Text manipulation with GAMAP ]]
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* [[Removing extraneous lines from map plots]]
  
== Memory management and CTM_MAKE_DATAINFO ==
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--[[User:Bmy|Bob Y.]] 09:48, 11 March 2011 (EST)
 
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When using CTM_MAKE_DATAINFO, you create few pointers and allocate memory to pointed data. Three scenarios to free that memory are possible.
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(1) By default, GAMAP keeps track of the pointers in a global structure, and you can clean up the memory by calling CTM_CLEANUP (with or without the keyword /NO_GC):
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    ctm_make_datainfo(data, ...)
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    CTM_WriteBpch, DataInfo, FileInfo, FileName=file
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    ctm_cleanup
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(2) If you use the keyword /NO_GLOBAL when calling CTM_MAKE_DATAINFO, the story is a little bit more subtle. Now, GAMAP has no idea of the created pointers. If you use CTM_CLEANUP without the keyword /NO_GC, everything is clean up because there is a call to heap_gc. But you are also loosing **all other** pointers and objects.
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    ctm_make_datainfo(data, ..., /No_global)
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    CTM_WriteBpch, DataInfo, FileInfo, FileName=file
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    ctm_cleanup
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Note if you do not call ctm_cleanup or call it with /No_GC, then the memory allocated by CTM_MAKE_DATAINFO is still allocated and the pointers that refers to it are alive... until you exit the routine (unless they are passed back). Once you are out of the routine, this memory remains allocated but is useless since unaccessible, in other words you have memory leak.
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(3) So, if you want to keep some objects and/or pointers alive in your code (i.e., you do not want to call heap_gc or ctm_cleanup,/no_gc), you need to free only the created pointers as follows:
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    ctm_make_datainfo(data, datainfo, fileinfo, ..., /No_global)
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    CTM_WriteBpch, DataInfo, FileInfo, FileName=file
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    ptr_free, DataInfo.data
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    ptr_free, fileinfo.gridinfo
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To free only the heap memory created by multiple calls to CTM_MAKE_DATAINFO, the procedure is:
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  for D=0L, NTracers-1L do begin
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      Success = CTM_Make_DataInfo( Data[*,*,D], DataInfo, FileInfo, ..., /No_Global )
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      ArrDataInfo = D eq 0l ? [ DataInfo ] : [ ArrDataInfo, DataInfo ]
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      if D ne Ntracers-1l then ptr_free, Fileinfo.gridinfo
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  endfor
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  CTM_WriteBpch, ArrDataInfo, FileInfo, FileName=OutFileName
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  for d=0, n_elements(ArrDataInfo)-1l do ptr_free, ArrDataInfo[d].data
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  ptr_free, fileinfo.gridinfo
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--Phs 2008/02/13 10:28
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Revision as of 14:49, 11 March 2011

On this page we list information about GAMAP, the Global Atmospheric Model Analysis Package.

Overview

GAMAP

  • is a self-contained, consistent, and user-friendly software package for reading and visualizing output from chemical tracer models (CTM's)
  • consists of a suite of routines written in IDL (Interactive Data Language)
  • makes extensive use of IDL's powerful plotting features
  • can produce line plots, 2D plots, 2D animations, or 3D isocontour surface plots
  • can read 2D, 3D or 4D data blocks
  • can read output from the GEOS–Chem, GISS and FSU model families
  • can be easily customized to keep pace with ongoing model development
  • can be installed on any platform that supports IDL, thus ensuring a high degree of portability
  • can be coupled with the ION (IDL on the Net) interface to create interactive plots which can be served to a web page
  • can read data from ASCII, binary, netCDF (including COARDS conventions!), and HDF–EOS file formats
  • contains helper routines to read from / write to various file formats

The main GAMAP program contains a user-friendly, menu-driven interface; however, users may also call GAMAP subroutines independently of the main program. This makes it possible to embed GAMAP routines within existing IDL code.

Table of Contents

GAMAP web pages

This page has now been split into several sub-pages:

GAMAP tips and tricks

--Bob Y. 09:48, 11 March 2011 (EST)