Released version 20.09 of GRAL GRAMM

gram gral  The Graz Lagrangian (GRAL) system is a Lagrangian particle model with a free Graphic User Interface (GUI) available in both Linux and Windows. Now the developers have released the version 20.09. The software is open source under a GPL-3.0 license, so everybody is welcome to contribute to the project. The source code, has been published in github.

    The version 20.09 of GRAL GRAMM has had some changes and modifications in the code, but focusing mainly in correcting bugs. No major features have been included in this update. See a list of issues solved here. The complete source code is published under the GNU/GPL 3 licence.


   This is the list of new features and bugs corrected for GRAL, GRAMM and the Graphic User Interface (GUI) for this release.

GRAL 20.09

New features

  • A new option “Adaptive Surface Roughness” (spatially varying surface roughness values) has been implemented
  • Ascending or descending line sources are supported
  • Additional user information
    - in the transient GRAL mode: average emission modulation, average exit temperature and exit velocity,
    date and time of the weather situation
    - show the progress when writing the concentration or the flow field files
  • Optional building input by using an ESRI ASCii format raster file
  • Additional separator characters for exit temperature and exit velocity files
  • Creation of additional transient particles in a cell with high pollution concentration
  • Better support for steep line sources
  • New flow field file format, designed for huge domains with terrain or many buildings


  • If artificially generated wind data with very small wind speed differences were used, the current situation of mettimeseries.dat was not assigned correctly in the file meteopgt.all in the transient GRAL mode
  • The changed file format for the file GRAL_Meteozeitreihe.dat has been fixed
  • A division by zero has been fixed (occurs in rare cases if there is no sub domain but a high surface altitude in cell [1][1])
  • The user defined sub domain factor was not applied to buildings
  • A warning message appears if the calculation is set to prognostic wind calculation, but no sub-domains have been created
  • The memory consumption and the number of page faults have been reduced
  • Erroneous transfer of roughness lengths when coupling with GRAMM in the Flow Field module has been fixed

GRAMM 20.09


  • Code clean up and performance improvements within the GRAMM radiation module
  • Removed experimental dependencies of Windows-GDAL, introduced in GRAMM 20.01, so that GRAMM works in LINUX again
  • Removed the experimental Topography Index algorithm (TPI)

GUI 20.09

New features

  • It is possible to delete items or edit item data (name, height, source group number, emission rate) within the spreadsheet search and filter form
  • Item information is shown in an own layer and is displayed geo referenced
  • A wind speed cumulative distribution diagram has been added
  • The legend and the info box within the wind rose form can be moved
  • Ascending or descending line sources have been enabled
  • Shape file types PointZ and PolylineZ are supported
  • It is possible to show solely already existing weather situations in the dispersion situation dialog
  • Multiple height slices can be selected for the evaluation of GRAL results
  • Enable access to special GRAL options from the GUI (wrench button)
  • The building rasterization process can be controlled by the user
  • The evaluation routines support large domain ranges by using jagged arrays
  • Enable a progress bar for the mathematical raster operations
  • Support for spatially-varying surface roughness values


  • Fixed the reading of the changed file format for the GRAL receptor meteorology file data (GRAL_Meteozeitreihe.dat)
  • Fixed the shape import for receptors
  • The anemometer height from *.met files is copied to the match to observation dialog
  • Fixed the 3D view of GRAL topographies with receptors
  • Fixed several tooltips
  • Fixed the GRAMM start process for the new *.exe GRAMM core for multiple instances
  • Fixed an error when creating the file IIn.dat with Taiwanese date format
  • Fixed a crash when the object manager was started but no layers were available
  • Improved reading of background maps when the absolute path in the bitmap world file has been changed
  • Fixed an error in the color and value settings for contour lines in the layout manager when a vertical scroll bar is visible
  • Fixed the selection of traffic situations in the NEMO line source dialog and a bug in the NEMO interface
  • Fix the windrose dialog for tabbed *.met files
  • Fix the meteorological analysis tool for empty or invalid *.met files
  • Enable large arrays for the evaluation of result files (> 2 GByte)

   The new version 20.09 is available on the GRAL homepage:



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