I am trying to determine the variables that predict forest fire occurrence in a region in Chile.
Firstly, I determined burned areas using LANDSAT data and the dNBR-index. I ultimately made a raster with 30m forest pixels with a value of 1 (burned) or 0 (not burned). I wanted to do a random sampling with minimum distance to reduce the autocorrelation between burned pixels. My problem is that I do not know to what distance my burned LANDSAT pixels are autocorrelated. I tried to make a semivariogram in R but this gave errors, probably due to the binary variable or because there are pixels with no-data values. I made a point shapefile of my raster for which every point has the same binary value of the pixel it is covering. However, if I make a semivariogram, I assume that the autocorrelation of pixels that were not burned isconsidered as well and this is not what I want.
Anyone an idea to investigate the autocorrelation of points or pixels with a specified value (1 in my case, which represents fire).