The calculation result of Area Solar Radiation is wrong, the values are approximated in a grid.

[久米俊郎]

I added the height of the building (raster) to the DEM to create a DSM.

 I input the DSM to Area solar radiation in Spatial Analyst and calculated the solar radiation, but the results were strange.
The values were approximated in a grid pattern.

 Incidentally, I used the default values for the parameters of Area solar radiation.
When I calculated only the height of the buildings, we did not see such a trend.

 If you have more information, please let me know!

[SteveLynch]

When you added the height raster:

- does it have the same cellsize as the DEM?

- and the same spatial reference?

- did you set SnapRaster=DEM when you added?

[久米俊郎]

Thanks for the advice!

 does it have the same cellsize as the DEM?-Yes

- and the same spatial reference?-Yes

- did you set SnapRaster=DEM when you added?-I used the raster calculator, but I could not set snap raster there.

[久米俊郎 · Accepted solution]

I checked again and found the same error when calculating solar radiation using only the DEM. This means that there was a problem with the DEM itself. I was using resample to match the cell size of the DEM to the cell size of the building raster, and the resampling_type of resample was NEAREST, which caused the problem. NEAREST is not suitable for continuous data. The problem was solved by using CUBIC, which is suitable for continuous data.