to_area

to_area(sids)

Returns areas of trixels of SIDs in sterdians.

Parameters:

sids: 1D array-like

SIDs to convert to areas

Returns:

area: 1D numpy arrau

areas of trixels of sids

Examples

>>> import math
>>> sids = numpy.array([4151504989081014894, 4161865161846704590, 3643626718498217166])
>>> pystare.to_area(sids)
array([5.41567334e-09, 5.46741649e-09, 4.98636938e-09])

>>> level = 8
>>> n = 8 * (4 ** level)
>>> level_increment = pystare.spatial_increment_from_level(level)
>>> sivs = [s+level for s in range(0, n*level_increment, level_increment)]
>>> area = sum(pystare.to_area(sivs))
>>> area/(4.0*math.pi)
1.000000000000014