Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. It only takes a minute to sign up.
Sign up to join this community
I have two raster datasets (maps of forest cover) and I would like to compare whether the data in these two rasters match.
Can someone please help me understand how to create random points and then extract the data (from both rasters) for these points, and later plot on a scatter plot in excel?
I use QGIS.
Option 1
Use raster calculator to compare each pixel with this expression "raster1@1"="raster2@1". It creates a binary raster (0/1) showing in black and white if pixels are identical or not.
Option 2
Create random points: Menu Vector / Research Tools / Random points in extent
Create new attributes for each raster using this expression: raster_value( 'raster',1,$geometry), replacing raster with the name of your raster layers and 1 with the number of the raster-band you want to get the value from. Repeat this/create a separate field for all raster-layers to be able to compare the values.
Then export the layer as CSV and open it in Excel for scatter plots. Or create scatter plots in QGIS with Data Plotly plugin.
