Blurring raster data across tile boundaries?

Question

I have a raster dataset that is made up of 280 tiles, 51Gb total. I need to smooth/blur the data, retaining the same resolution. I would like to blur across tile boundaries, where possible, so that points on the edge of each raster contain information from the neighbouring raster(s). I would like the output to be in the same format or smaller tiles.

I there an easy way to do this? I see that it's possible to blur using a KernelFilteredSource in VRT, but it's not clear how that can be made to work across tile boundaries.

I guess the other option is to write a script to load each tile, plus the margins from the surrounding 8 tiles, blur the result, trim, and re-save. I'm just wondering if there's a more efficient way to do it before I try that.

Answer 1

You can write two .VRT files and use them chained:

1. Create a .VRT that mosaics all your source files into one virtual layer with gdalbuiltvrt https://www.gdal.org/gdalbuildvrt.html

2. Make a new vrt that is referencing this Mosaic as gdal_translate -of vrt mosaic.vrt filtered.vrt

3. Edit filtered.vrt and turn it into KernelFilteredSource as in the answer How to convert GeoTIFF to grayscale and add gaussian blur? and as documented in https://www.gdal.org/gdal_vrttut.html