when using a WPS to download data, the download estimator can check various parameters (like maximum raster dimensions, maximum feature number, etc) to allow the download process to run or not, in order to avoid producing large datasets or cause the server to run out of resources. The download estimator calculations regarding raster datasets currently take into account only source and output raster pixel dimensions, and ignore raster bands. By using raster band indices selected for the output dataset as a parameter for the download estimation process, we may end up having a more accurate estimation of the raster output size.
The most straightforward solution is to calculate the raw raster size based on the pixel dimensions and the size of the sample type for each band of the resulting raster. However, this is an upper limit, since compression reduces final size. On the other hand, one cannot easily calculate compression ratio beforehard, so finding a more realistic estimation of the final file size beforehand is not trivial.