Hi Paulo, you could use a focal analysis approach using the "terra" package. You could build for each category (e.g., "urban", "forest", etc) a raster with an indicator coding (1 and 0) and then apply simple kernel (weight matrix, as below) doing the summation of the neighboring pixels.
1 1 1 1 NA 1 1 1 1 If the resulting pixel (at the center of the kernel) is >0 means that one of the neighboring pixels is of the considered category. But maybe there are specialized packages doing directly this. Sincerely, Sebastiano * Sebastiano Trevisani, Ph.D.* * Associate Professor* *Applied and Environmental Geology* * https://orcid.org/0000-0001-8436-7798 <https://orcid.org/0000-0001-8436-7798>* *IUAV University of Venice: www.iuav.it <http://www.iuav.it/>* *Address: Dorsoduro 2206, Venice 30123, Italy Tel: +39. 041. 257 1299Mail: strevis...@iuav.it <strevis...@iuav.it> * *"Le opinioni espresse sono riferibili esclusivamente all'autore e non * * riflettono in alcun modo una posizione ufficiale dello IUAV "* *"The views expressed are purely those of the writer and may not in any circumstances be regarded as stating an official position of the IUAV."* On Tue, Nov 9, 2021 at 6:40 PM Paulo Flores Ribeiro < paulo.flores.m...@gmail.com> wrote: > I would like to create a raster from an existing one, where each pixel > in the new raster is set to 1 if the corresponding pixel in the existing > map is in the direct neighbourhood (8 neighbouring pixels) of at least 1 > pixel with a particular value, or 0 if otherwise (e.g., create a raster > that identifies all "agricultural" pixels that are neighbours of "urban" > pixels). How to do this in the most computationally efficient way? > Thanks in advance, PauloFR > > _______________________________________________ > R-sig-Geo mailing list > R-sig-Geo@r-project.org > https://stat.ethz.ch/mailman/listinfo/r-sig-geo > [[alternative HTML version deleted]] _______________________________________________ R-sig-Geo mailing list R-sig-Geo@r-project.org https://stat.ethz.ch/mailman/listinfo/r-sig-geo