I have irregular gridded data and I wish to resample from this data in such a way that the spatial correlation in the data is preserved. I will assume that grids that are within 300Kms of one another are correlated. I have 153 grids in all and some grids have 2 neighbours (i.e. 2 grids that lie within 300 kilometres) and some grids have as many as 11 neighbours. I wish to know how to draw a bootstrap sample from this grid. My ultimate objective is to run a regression on the gridded data that I have to get at the distribution of the standard error of the regression coefficient. Many thanks!