"Transform" Centroids into GeodataFrames

[chahank]

The centroids objects are essentially a manually created GeoDataframe. The code could be simplified by making an attribute .gdf to hold the data. The only attribute that breaks this currently is the meta to describe rasters. However, since all of CLIMADA internally works with vector data and does not support rasters, we could drop this and only use rasters in I/O operations.

[peanutfun]

Excellent idea! This would probably simplify a lot of the internals. The way I see it, all attributes except meta can be stored as columns in the GeoDataFrame. Some backwards-compatibility (for both the internals and external access) can be provided through accessors like

@property
def elevation(self):
    return self.gdf["elevation"]