Bug report #3167
calculation of ruggedness
|Affected QGIS version:||Regression?:||No|
|Operating System:||All||Easy fix?:||No|
|Pull Request or Patch supplied:||Resolution:||wontfix|
|Crashes QGIS or corrupts data:||Copied to github as #:||13227|
In browsing the code for ruggedness I found something odd.
The formula is missing division by n prior to the execution of sqrt if it is supposed to be standard deviation from the centre pixel.
Since there is no documentation on the formula that was intended, I don't know if this is intentional or a bug.
#1 Updated by Marco Hugentobler almost 10 years ago
- Resolution set to wontfix
- Status changed from Open to Closed
Ruggedness index is calculated according to Riley et al. 1999 (see corrected formula in http://www.fw.msu.edu/~rileysh2/Terrain%20Ruggedness%20Index.pdf). There is no division by the number of pixels, only the root of the squares is taken.