Naming clipped files from layer mask?

Question

I have to clip a quite large raster (corn crops) into individuals rows. It's working fine with the "Clip raster by mask layer" tool with a grid I created.

However, I need the clipped images to be named after the mask feature that's been used.

I've created a new feature in the grid so every cell is named how I want it to.

Is there a way to do so?

Answer 1

If you've split the grid into individual layers that are saved in a directory, then you can select that directory (using Autofill...) as the Mask layer field for Clip raster by mask layer tool in Batch Processing mode.

Then for the Clipped (mask) field, select Autofill... -> Calculate by expression, and use an expression like:

file_path(@MASK) + '\\' + base_file_name(@MASK)+'.tif'

to translate the mask filenames into corresponding output filenames. Obviously you may need to play with the details to get it to work for your filesystem.

Answer 2

You can use pyqgis and iterate over each polygon, create a temp mask layer using its id, clip using the mask layer:

import os
output_raster_folder = r"C:\temp\test" #Adjust
rasterlayer = QgsProject.instance().mapLayersByName("land_use")[0] #Adjust
vectorlayer = QgsProject.instance().mapLayersByName("clip_layer")[0] #Adjust
name_field="name" #Adjust

for feature in vectorlayer.getFeatures(): #For each polygon in vectorlayer
    
    #Create a temp layer using current feature id
    masklayer = vectorlayer.materialize(QgsFeatureRequest().setFilterFid(feature.id()))
    name = next(masklayer.getFeatures())[name_field] #Fetch its name from name_field

    print(f"Clipping polygon: {name}")
    #Create output raster name using the name: #Example: 'C:\\temp\\test\\clip_c669.tif'
    output_raster = os.path.join(output_raster_folder, f"clip_{name}.tif") #Adjust if you want to 
    
    #Clip using the temp layer of only one polygon feature
    processing.run("gdal:cliprasterbymasklayer", {'INPUT':rasterlayer,
    'MASK':masklayer,'SOURCE_CRS':None,'TARGET_CRS':None,'TARGET_EXTENT':None,
    'NODATA':None,'ALPHA_BAND':False,'CROP_TO_CUTLINE':True,
    'KEEP_RESOLUTION':False,'SET_RESOLUTION':False,'X_RESOLUTION':None,
    'Y_RESOLUTION':None,'MULTITHREADING':False,'OPTIONS':'COMPRESS=LZW',
    'DATA_TYPE':0,'EXTRA':'','OUTPUT':output_raster})