I found the SAGA-Module "Topographic Openness" and it seems to fit my requirements quite well. Only thing I am wondering about is, what do the resulting values of positive/negative openness exactly stand for or rather how can they get transformed to angle values? I read the article from Yokoyama et al. (2002) about openness which is referenced by the Module Library Documentation and understand, that the resulting openness values should be the mean value of all zenith/nadir angles along each computed profile. Using SAGA the result is somethin between 1.25 and 1.61 or so. A constant raster surface gives a constant value of 1.57 (which should equal 90°(?)).
I am using version: 3.0.0
Any help is appreciated.
Thanks
Hans
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...i can confirm that the openness output unit is radians. for the next saga release i added this information and also added an output unit option for degree.
best wishes,
olaf...
If you would like to refer to this comment somewhere else in this project, copy and paste the following link:
Hello all,
I found the SAGA-Module "Topographic Openness" and it seems to fit my requirements quite well. Only thing I am wondering about is, what do the resulting values of positive/negative openness exactly stand for or rather how can they get transformed to angle values? I read the article from Yokoyama et al. (2002) about openness which is referenced by the Module Library Documentation and understand, that the resulting openness values should be the mean value of all zenith/nadir angles along each computed profile. Using SAGA the result is somethin between 1.25 and 1.61 or so. A constant raster surface gives a constant value of 1.57 (which should equal 90°(?)).
I am using version: 3.0.0
Any help is appreciated.
Thanks
Hans
O. K. sorry about the post... ;-)
90 degrees or ~1.57 rad
I was wondering the same thing. Only radians makes sense as unit but it would be nice to have a confirmation of that. :)
hello dear all,
...i can confirm that the openness output unit is radians. for the next saga release i added this information and also added an output unit option for degree.
best wishes,
olaf...
Thank you! That will help other users as well. :)