Yes, this looks very good, thanks!

@khaeru : I had the same question and just tested it:

``` python import xarray as xr import numpy as np

@xr.register_dataset_accessor('geo') class GeoAccessor(object): def init(self, xarray_obj): print('In constructor') self._obj = xarray_obj

@property
def center(self):
    # return the geographic center point of this dataset
    lon = self._obj.latitude
    lat = self._obj.longitude
    return (float(lon.mean()), float(lat.mean()))

def plot(self):
    print('plot data on a map')  # e.g., using Cartopy

Nothing is printed

ds = xr.Dataset({'longitude': np.linspace(0, 10), 'latitude': np.linspace(0, 20)})

out: In constructor

out = ds.geo.center

out: In constructor

plot data on a map

ds.geo.plot() ```

So the constructor is called only if the property is accessed, which is good. the drawback is that a new object is instantiated at each access.