I've used QGIS's Polygonize to convert the following raster into outlines. The polygonize tool does produce a vector output, but it isn't in plain polygon form but some thousands of single pixel polygons.
I understand that this is the expected behavior of the Polygonize tool and one can now simplify these weird squares for it to just be two polygons - one for brown and one for purple. I tried setting a really low threshold of 0.000001 for v.generalize (in the Processing toolbox) for these shapes to be converted into a line and yet there seems to be no improvement. The documentation of v.generalize did not seem too useful.
How does one go about making this into two plain polygons?