Calculating mean of raster layers where some layers have missing values using QGIS

Question

How do I create annual averages of raster layers, if some of these layers have gaps in the data?

If all pixels in all of the layers contained info I would just use Raster Calculator and do (r1 + r2 + r3 +...)/n.

However, the number of layers including useful information for each pixel isn't the same across the rasters so I am not sure how to proceed.

I am very new to spatial analysis and to working with rasters in QGIS.

Answer 1

I think there are two ways.

1. Calculate by interpolating the missing values.

• The average is obtained from the corrected value.

2. The mean is calculated only when each cell has a value other than Nodata.

• If you use only the QGIS raster calculator, first classify the values of each raster as 1 and nodata=0.
• Adds all rasters.
• You will be able to extract areas of raster with overlapping values through raster values. (If there are 3 rasters, the possible values are 0-3.)
• Select each area to make a mask and then calculate the value of the original data.