Compiling SAGA on Linux

Landemaine — Tue, 21 Apr 2026 12:51:25 -0000

Hi,
We have developed our own SAGA module as a dynamic library (.dll) using the Windows version, and it works correctly.
However, in order to use it on our Linux compute server, we would like to create a Linux-compatible version.
Is it possible to compile our module under Linux so that it can then be integrated into a SAGA installation on Linux? If so, where can we find the relevant documentation?
Best regards,
Valentin

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Andrea Giudiceandrea — Sat, 28 Feb 2026 11:15:56 -0000

I've used QGIS 3.40.15 and SAGA-GIS 9.11.1 (both from OSeo4W) and the "Processing Saga NextGen Provider" plugin 1.1.0 and I've obtained realistic values for an area in the South of Italy just setting the parameters "Time period" to "Range of days", range of days between 1/1/2025 and 31/12/2025 and Resolution to 15 days, among the others:

Total Insolation have values between 1303-2140 kWh/m^2

Andrea Giudiceandrea

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Renato Forte — Fri, 27 Feb 2026 14:26:18 -0000

Ok, thanks, I'll re-try, maybe it's a problem of my QGIS version.

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Volker Wichmann — Fri, 27 Feb 2026 14:23:32 -0000

Hi Renato,

first of all, you should get only one output grid in case you are interested in the annual insolation. To compute this grid, use the following settings:

Time Period: range of days
- Day: first day in year (2025-01-01)
- Last Day: last day in year (2025-12-31)
- Resolution [d]: e.g. 5, then each 5th day in the time period will be simulated
Time Span [h]: 0;24 (compute whole days from 0:00 o'clock to midnight)
Resolution [h]: e.g. 1 hour (compute a day in 1 hourly steps)

With these settings you get a single grid which you can store to GeoTiff (as single band) or in SAGA format.

I'm not familiar with QGIS, but you should be able to load the single band GeoTiff without problems. As QGIS also uses the GDAL library to read raster data, you can also load grids in SAGA's .sg-grd-z compressed file format or the .sgrd format (with the latter you must select the .sdat file for import). I don't know if you must use a special GDAL import raster tool in QGIS to load these formats.

Best regards,
Volker

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Renato Forte — Thu, 26 Feb 2026 23:41:11 -0000

Hello Volker,
I've processed my DSM directly in SAGA GUI (Saga.9.11.13), using potential annual insolation (14 steps, resolution h 1, reference year 2025. So, I suppose starting 01-01-2025 with time steps of about 26 days).
I saved my outputs as a multi band GeoTiff, then also as a SAGA compressed and uncompressed sg_gds grid collections (with right click on the file in SAGA and "save as").
I have now an Annual Insolation_DSM.tif file,
an Annual Insolation_DSM.sg-gds-z file,
and then the series of 15 uncompressed file Annual Insolation_DSM.sg-001 to sg-015 (and the 4 auxiliary file sg-att, sg-gds, sg-info, sg-prj).
Now, if I drag-and-drop in QGIS directly the sg-gds-z file or the sg-gds files, I get of course error from QGIS (invalid data source) because the format is not compatible.

While if I drag-and-drop the Annual Insolation_DSM.tif file in QGIS, it is being displayed, but only the first 3 time steps: 2025-01-01, 2025-01-27 and 2025-02-22 as 3 different RGB bands (see attached screenshot).

I don't want to display the single SAGA steps, but the total result, that is the overall solar insolation in a year: my goal is to display a single band GeoTIFF raster showing the total annual insolation, that is each pixel should have the total value of solar insolation received in one year (in kWh/mq) . The range of pixel values should be more or less: min 134,92 - max 1755,11, as in the attached picture (see Total_Annual_Real_Insolation_Lumped_AT70.tif).

So, my question is: how can I properly display in QGIS the Annual Insolation_DSM.tif that I produced with SAGA?

I've also exported from SAGA my annual insolation file using io_gdal, in geoprocessing/ file/grid/export/export GeoTiff, but when I add the GeoTiff file in QGIS I still get the identical result (that is only the first three steps displayed as 3 different RGB bands).
Maybe I should convert the single sg files and sum them in SAGA? Or perhaps is there a particular export procedure in SAGA which I am not aware of?

Apologies for such a long post, and many thanks in advance for any help.

Kind regards,
Renato

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Renato Forte — Thu, 26 Feb 2026 13:03:09 -0000

Ok, thanks, I'll try and will let you know

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Volker Wichmann — Thu, 26 Feb 2026 13:01:07 -0000

Hi Renato,

the interface shown in the screenshot is not correct when the "range of days" option is selected. Maybe the tool wrapper used in QGIS is incomplete and does not parse the parameters correctly. Please test with SAGA and call the tool from SAGA GUI (saga_gui.exe), this should provide you correct outputs.

Best regards,
Volker

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Renato Forte — Thu, 26 Feb 2026 12:53:18 -0000

Hi Volker, thanks for your prompt reply.
I'm using SAGA version 9.10.2, through QGIS 3.40.15-Bratislava (in QGIS: Processing, Instruments/SAGA/Terrain Analysis/Potential incoming Solar Radiation)
When I select "range of days", I insert 2025‑01‑01 and 2025‑12‑31 for time span, with a resolution [d] of 5 (days).
But the options Moment [h]: 12,0000 and Resolution [h]:0,50000 are still active. Anyway I left their values unmodified, with default values.
Attached the screenshot of adopted parameters (in particular the second screenshots).
Is there anything wrong with my time parameters?
Or maybe I should run SAGA not from QGIS but using an other interface?
In the log window I can read that there's a problem with Saga version: Problem with SAGA installation: unsupported SAGA version (found: 9.10.2, required: >=9.2.).
If needed I can copy and paste the entire log report.
In the meantime please let me know if you can see some wrong parameters in the pictures.
Thanks again and best regards,
Renato

Annual Potential incoming solar radiation with Saga, how to set the time parameters?

Volker Wichmann — Thu, 26 Feb 2026 08:17:48 -0000

Hi Renato,

when you select "range of days", there is no "Moment" parameter but a "Time Span" parameter instead. When I use that (0;24h) and you settings I get reasonable results with your other settings.

The main question is thus: why do you see the "Moment" parameter instead of the "Time Span" parameter? This should not be the case when you use the tool in SAGA, do you use any other interface like QGIS?

Best regards,
Volker

Potential Annual Insolation-How to calculate it in SAGA?

Renato Forte — Thu, 26 Feb 2026 02:54:47 -0000

Hello Volker, I'm trying exactly the same analysis, using range of days from 2025-01-01 to 2025-31-12, with resolution 15 (time steps of 15 days). But the sdat file in output shows pixel values totally unrealistic, ranging from 0.31 to 6.1 kWh/m². How come that ? what I'm doing wrong? or perhaps the pixe values in output are the average DAILY values of solar radiation? if I multiply by 365 the range become quite realistic for my area of study! can you please give me some hints? thanks in advance!

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