Potential incoming solar radiation

User Forum
  • Grange

    Grange - 2012-05-04


    I am new to this forum, I just started using SAGA today. I would need a little
    help for calculating the incoming solar radiation. I opened my grid file, and
    when I launch the calculation it is recorded as 'failed' and an error message
    says ''module caused acces violation". What can I do?

    Thank you for your help :)

  • man_e

    man_e - 2012-05-04


    only with the information given in your post, it is quite hard to give you
    detailed help.

    This error message is often the result of insufficient system memory (RAM). So
    please have a look at the size of your dataset and the memory used by the SAGA
    process. Also keep in mind that SAGA requires additional memory during the
    module execution.


  • Grange

    Grange - 2012-05-04

    in the 'properties' it says memory use normal, so i guess this is not the
    problem but thank you :)

    I think my grid did not open properly: it is a a digital elevation model of
    france and the data doesn't seem correct (the maximum height is about 250 as
    in reality it can go up to 800). I don't really understand....

  • man_e

    man_e - 2012-05-04

    the "memory handling" normal in the setting only indicates that the dataset is
    not cached or compressed. Furthermore the value range is only valid for the
    color settings in the map (default it is set to 1.5 * standard-deviation, not
    min-max). The actual min max values can be found in the description tab on the
    right side. At the bottom you can find the point "memory size" which shows the
    size used by the dataset in the memory. If you are using a 32 bit SAGA, the
    all datasets loaded in the application can not exceed 2 gb in size.


  • Hosein

    Hosein - 2013-12-16

    Hi SAGA users,
    I am new with SAGA, I really need to calculate incoming solar radiation for my thesis in raster format.
    I have only DEM raster file, as far as I know, we should have 3 raster files (DEM, Dust, Water vapor pressure), Am I right?
    I don't know what I do. Is any one have a sample files to calculating incoming solar radiation?
    Thank you for your consideration. :)

  • Volker Wichmann

    Volker Wichmann - 2013-12-17

    The only mandatary input is an elevation dataset, the waterpressure grid is optional (i.e. you can provide one in case you have spatially distributed information, otherwise a global parameter value is used). I think dust is always provided as global parameter.

  • Kegley

    Kegley - 2014-04-15

    Hi, I have just discovered this wonderful software as I need to to some solar analysis.

    However I have a technical question, forgive me if this is an obvious question for specialists but it is not for me and I was unable to find any documentation on the site:
    The output produced by the tool is a raster dataset with a value for each cell. But what does this value represent?

    I mean in terms of units. Is it a generalized value like watt hours per square meter or something else like watt hours incident on the cell? (In which case it depends on the size of the cell).

    Also, the first reference given for the module is
    Boehner, J., Antonic, O. (2009): Land Surface Parameters Specific to Topo-Climatology. in Hengl, T. & Reuter, H.I. : Geomorphometry - Concepts, Software, Applications.

    Is it safe to assume that the algorithm used to compute these values is identical to the algorithm given in that chapter of the publication?

    Thank you in advance!

    Last edit: Kegley 2014-04-15
  • Volker Wichmann

    Volker Wichmann - 2014-04-17

    But what does this value represent?

    You can choose the unit of the output, either kWh/m2, kJ/m2 or J/cm2. Thus it is independent of the cell size.

    Is it safe to assume that the algorithm used to compute these values is identical to the algorithm given in that chapter of the publication?

    Yes, in principle. The Atmospheric Effects methods two and three are TAPES-G based, for which you should have a look at Wilson & Gallant. But I see that these are still labelled as experimental.


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