Support transformations of coordinates given as numpy arrays

[coroa]

The docstring of Proj.__call__ states that it would be possible to pass an ndarray of shape (n,2), but the supporting code is commented out in __call__ as well as the cython defined methods of _invn and _fwdn.

What is the problem with these? It would help a lot if they were supported again.

[BrenBarn]

I just came across this as well. What the heck is going on there?

[timothyb0912]

I also had a problem today when I wished to use the support for arrays but encountered the following error when passing an array of shape n,2 to the projection instance: ValueError: need more than 1 value to unpack.

The documentation should at least be changed so as not to mislead people into thinking that there is support for arrays.

[danielramosg]

Same error for me. Can someone give an explanation of why numpy arguments are no longer supported? It would help a lot if fixed.

[ghost]

I think Transformer.transform() recently introduced with #189 closes this longstanding issue.

[snowman2]

Here is the current recommended method to transform 2D numpy arrays with pyproj 2.x:

>>> from shapely.geometry import LineString, Point
>>> import numpy
>>> ll = LineString([Point(ii, ii) for ii in numpy.arange(0, 90, 0.01)])
>>> points = numpy.asarray(ll)
>>> points
array([[0.000e+00, 0.000e+00],
       [1.000e-02, 1.000e-02],
       [2.000e-02, 2.000e-02],
       ...,
       [8.997e+01, 8.997e+01],
       [8.998e+01, 8.998e+01],
       [8.999e+01, 8.999e+01]])
>>> from pyproj import Transformer
>>> transformer = Transformer.from_crs("epsg:4326", "epsg:3857")
>>> points_3857 = numpy.empty(points.shape)
>>> points_3857[:, 0], points_3857[:, 1] = transformer.transform(points[:, 0], points[:, 1])
>>> points_3857
array([[0.00000000e+00, 0.00000000e+00],
       [1.11319491e+03, 1.11319491e+03],
       [2.22638982e+03, 2.22638986e+03],
       ...,
       [1.00154146e+07, 5.26064404e+07],
       [1.00165278e+07, 5.51925525e+07],
       [1.00176410e+07, 5.96135402e+07]])

[snowman2]

I believe with #38 and #4 (comment), this issue has been resolved. Feel free to continue the discussion if you have further questions.