H3fy concats pandas dataframes for each polygon in source_unary

[jtmiclat]

Hi was looking h3fy implementation and I found the following lines https://github.com/pysal/tobler/blob/66f3825594cf5a3b00ca351b9356cedea5884b86/tobler/util/util.py#L97-L102

It runs pd.concat for each polygon in source_unary. It should probably run pd.concat only once and outside the for loop like

        output = []
        for geom in source_unary.geoms:
            hexes = _to_hex(geom, resolution=resolution, return_geoms=return_geoms)
            output.append(hexes)
        hexagons = pandas.concat(output) # unindent

[knaaptime]

good catch, thanks!