Latest Contributions by ToddMcDonnell

Hello, I am adding four different grids: RasterA + RasterB + RasterC + RasterD; and am interested in expressing uncertainty in the results based on uncertainties in each of the input grids. All grids are in the same units and all values are positive in the range of zero to about 200. The values in each grid have different ranges of uncertainty, such as: +/- 6 for RasterA +/- 10 for RasterB +/- 12 for RasterC +/- 5 for RasterD I would like to run a monte carlo style analysis whereby the grids are added to together multiple times (e.g. n = 1000) based on values for each grid cell that are randomly selected from within the uncertainty range around each input grid cell value. Does anyone have suggestions for how to carry this out or know of any available tools/code? Thanks in advance. ... View more

I am using the Moran's I tool to check for spatial autocorrelation in the residuals generated from the OLS model to determine if geographically weighted regression might be appropriate for the data. I am wondering what the Moran's I tool uses to calculate the z-score? I have read the documentation and it seems that it determines the difference between each residual value and the mean of all the residuals, and then checks to see if these magnitudes are clustered or dispersed (or random). Can someone verify my interpretation and/or provide additional explanation? ... View more

I need to convert a 30m elevation grid to a grid that gives values for the cell latitude rather than elevation. I tried converting the GRID to point, adding x,y data to the points, then converting back to GRID using the y-coordinate as the value, however, the large region I am working with is preventing the processes from completing successfully. Any advice will certainly be appreciated. Todd ... View more