'**SUMMARY**
Returns a sorted FeatureSet with the features closest to a given coordinate first.
Default is from the center of the image.
**PARAMETERS**
* *point* - A point on the image from which we will calculate distance.
**RETURNS**
A numpy array of distance values.
**EXAMPLE**
>>> img = Image("lenna")
>>> feats = img.findBlobs()
>>> d = feats.sortDistance()
>>> d[-1].show()  #show the 0th blobs distance to the center.'

def sortDistance(self, point=((-1), (-1))):

    return FeatureSet(sorted(self, key=(lambda f: f.distanceFrom(point))))
