I have shp of points where each point is the centroid of the individual cells of a 1*1km grid (~ 500 000 points). For each of these points, I have their coordinates and elevation.
What I want: for each of these points, I want to compute the mean, std dev, min, max and median elevation of the nearest 8 surrounding points.
What I did so far: I wrote an R script to identify each of the nearest points for each of the points of the grid. But considering the size of the dbf and the general slowness of R, it takes forever.
My tools: QGIS, ArcGIS, SAS, R or other free software if needed.
Does any one have a suggestion to do this (1- identify the direct neighbors, 2- compute summary stats from the elevation of these neighbors) in a more efficient way, using GIS?