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I have two datasets that I want to compare against each other within a defined shapefile boundary, within a defined yearly range EG (2000-2020)

a) A burned area raster for each year in the range.

b) A forest loss raster for each year in the range

These are classified as 1 = loss, 0 = no data.

My aim is to compare these against each other to see where they overlap for each year within the range. The output should be a CSV file which states the "Burned Forest Area" each year in hectares. EG 2000 - 450ha, 2001 - 1300ha, etc.

A solution could loop through for each year, and record a value where the area is both forest loss = 1, and burned area = 1

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  1. Raster calculator each year, raster1*raster2
  2. Extract by mask
  3. Add all layers to the map

1 and 2 can ofc be done using python...

Iterate over them and try something like:

import csv, re

pixelsize = 500
yearly_data = []

for rasterlayer in QgsProject.instance().mapLayers().values():
    stats = processing.run("native:rasterlayerstatistics", {'INPUT':rasterlayer,'BAND':1,'OUTPUT_HTML_FILE':'TEMPORARY_OUTPUT'})['OUTPUT_HTML_FILE']
    with open(stats, 'r') as f:
            for i, line in enumerate(f):
                if i==5: #Line 5 is raster sum
                    sum_of_pixels = float(re.findall('\d*\.?\d+', line)[0])
                    area = sum_of_pixels*pixelsize**2
                    print('Area year {0} is: {1} m2'.format(rasterlayer.name(), area))
                    yearly_data.append([rasterlayer.name(), area])
            

with open("/home/bera/Desktop/out.csv", "w", newline="") as f:
    writer = csv.writer(f)
    writer.writerows(yearly_data)

enter image description here

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