I'm trying to replicate the calculations performed by a Javascript application in Python. The calculations are based on the intersection between a set of points (in WGS84) and a polygon (in NAD83). Depending on which transformation I specify in the Python application, the number of points within a given polygon is consistent with the Javascript application for some polygons, and not for others. I believe it I could specify the correct transformation (the one used in the Javascript application) in the Python application, I would get the correct result.
The Javascript application does not specify a transformation, so I am assuming that it uses whichever is the default.