def aggregate(raster, ndv, block_size):
raster2 = block_reduce(raster, block_size, func=np.ma.sum)<EOL>return raster2<EOL>
Aggregate raster to smaller resolution, by adding cells.
Usage:
        aggregate(raster, ndv, block_size)

where:
        raster is a Numpy array created by importing the raster (e.g. geotiff)

        ndv is the NoData Value for the raster (can be read using the get_geo_info function)

        block_size is a duple of factors by which the raster will be shrinked

Example:
        raster = HMISea.tif

        ndv, xsize, ysize, geot, projection, datatype = get_geo_info(raster)

        costs = load_tiff(raster)

        costs2=aggregate(costs, ndv, (10,10))