mask_raster_by_raster.md

Mask a raster by another raster(with NoData) using rasterio

An update-to-date solution to following questions:

• https://gis.stackexchange.com/questions/26893/creating-shapefile-showing-footprints-of-rasters
• https://gis.stackexchange.com/questions/61512/calculating-image-boundary-footprint-of-satellite-images-using-open-source-too

Variables used:

• RASTER1: the raster to be masked
• RASTER2: the raster to act as mask, usually with NoData (around data)
• MASK.geojson: the footprint of valid data from RASTER2
• OUT_RASTER: the output file path

Steps:

1. Convert RASTER2 to vector MASK.geojson

rio shapes raster.tif --mask --collection --crop > MASK.geojson

2. Use vector MASK.geojson to mask RASTER1

rio mask RASTER1 OUT_RASTER --geojson-mask MASK.geojson

1. When masking(step 2), you may use --crop option to change the extent of the output raster to the mask extent. This is much faster when the mask area is small comparing to the raster extent.
2. When masking, you may also use gdal cli tools. This can be much faster.

gdalwarp  -cutline mask.geojson -crop_to_cutline in.tif out.tif