similarity

[DanielJDufour]

Is your feature request related to a problem? Please describe.
Should probably come up with a way to compare similarity of two rasters, drawing inspiration from: https://github.com/danieljdufour/polygon-similarity (which aligns rasterized polygons to the same grid)

Describe the solution you'd like

geoblaze.similarity(a, b)
0.7

Describe alternatives you've considered
Maybe something like https://www.npmjs.com/package/pixelmatch

Additional context
Could probably leverage rasterCalculator which should do the alignment. Similarity would just be basically running a special function over the raster