[GRASS-user] How to use r.horizon output work with r.sun

GRASS GRASS user
1

Hello,

I’m sorry if this was sent twice. I’m unsure if my first attempt to send this was successful.

I am trying to generate total radiation grids using r.sun, but when I use the outputs of r.horizon with r.sun, no output file is created. I ran r.horizon for all angles between 0 and 360 with an angle step of 5. However, I ran the angles in separate tool windows. I used the same base name for all runs of r.horizon, but these files don’t seem to work together in r.sun.

I have tried running r.sun without r.horizon inputs and it works. I was going to try running all horizon angles within a single tool window, but the run time for all 72 angles is almost 20 days, so that’s not a feasible option for me.

Are the outputs of r.horizon marked in some way (besides having a consistent base name) to allow these files to work together in r.sun? If so, can I mark the files that I created from separate runs of r.horizon in the same way?

Photos below show my workflow.

  1. Load in the 30-m DEM and set computation extent to the boundary of California.

  2. Use multiple windows of r.horizon to generate 72 horizon rasters.

    1. Use r.sun to generate global irradiance grid.

  7. There is no output file created.
    Thank you,

Helen

2

Hi,

I don’t see anything wrong here, so my suggestion would be to replicate your workflow on the NC sample dataset and see if that works properly. If not, then it would be easier for us to figure out what’s wrong. If the workflow works on the NC dataset, but not on CA, the problem could be perhaps that the r.sun process crashes due to insufficient memory or a bug.

Anna

On Wed, May 11, 2022 at 10:30 PM Helen Kesting <hkesting@unr.edu> wrote:

Hello,

I’m sorry if this was sent twice. I’m unsure if my first attempt to send this was successful.

I am trying to generate total radiation grids using r.sun, but when I use the outputs of r.horizon with r.sun, no output file is created. I ran r.horizon for all angles between 0 and 360 with an angle step of 5. However, I ran the angles in separate tool windows. I used the same base name for all runs of r.horizon, but these files don’t seem to work together in r.sun.

I have tried running r.sun without r.horizon inputs and it works. I was going to try running all horizon angles within a single tool window, but the run time for all 72 angles is almost 20 days, so that’s not a feasible option for me.

Are the outputs of r.horizon marked in some way (besides having a consistent base name) to allow these files to work together in r.sun? If so, can I mark the files that I created from separate runs of r.horizon in the same way?

Photos below show my workflow.

  1. Load in the 30-m DEM and set computation extent to the boundary of California.

  2. Use multiple windows of r.horizon to generate 72 horizon rasters.

    1. Use r.sun to generate global irradiance grid.

  7. There is no output file created.
    Thank you,

Helen

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