Feature Request: i.variance

[AndrewCunliffe]

Please consider adding support for i.variance https://grass.osgeo.org/grass-stable/manuals/addons/i.variance.html described well here. We're not aware of another implementation of this in R, and currently we're using GRASS only to implement this for analysis in a few projects.

As Woodcock and Strahler (1980) write: "The reasoning behind this measure is as follows.

• If the spatial resolution is considerably finer than the objects in the scene, most of the measurements in the image will be highly correlated with their neighbours and a measure of local variance will be low.
• If the objects approximate the size of the resolution cells, then the likelihood of neighbours being similar decreases and the local variance rises.
• As the size of the resolution cells increase and many objects are found in a single resolution cell, the local variance decreases."

We think that this i.variance metric (and specifically the variance/resolution plots) might be more nuanced and informative than the (semi)variograms that are often used to characterise and understand spatial structure in the biophysical environment