How do I map points from a CSV file against bands in a raster?

Question

I have a series of biome maps in QGIS 3.32 as multiband (RGB) raster layers. In a separate layer I have a series of points imported from a CSV file. How do I go about mapping the points (or rather a filtered subset thereof) from the delimited text file against the biomes in one of the multiband rasters? For example, to map the number of points that fall within the tundra biome.

I had thought of converting the rasters into vectors and then mapping the points of one layer against the attributes of the other. My attempts to polygonise the rasters, however, only allowed for one band to be carried over as an attribute. Likewise my attempt to transform them into csv files did not work.

Does anyone have a suggestion about how to go about doing this? Any help would be deeply appreciated.

Answer 1

Instead of vectorizing your raster and aggregating the data in your raster-vector you could do the opposite:

Sample the raster at the location of each point and aggregate it from there. You can do this with the

Sample Raster Values Tool

Input Layer: your points

Raster layer: your Biome-raster

Note: It may fail, if you try to use the CSV as input. In this case you need to save the file as a .shp or .gpkg (right click in Layer overview -> Export)

If you scroll down here a bit, you can find a ste-by-step guide: enter link description here