cart2pol#

movement.utils.vector.cart2pol(data)[source]#

Transform Cartesian coordinates to polar.

Parameters:

data (xarray.DataArray) – The input data containing space as a dimension, with x and y in the dimension coordinate.

Returns:

An xarray DataArray containing the polar coordinates stored in the space_pol dimension, with rho and phi in the dimension coordinate. The angles phi returned are in radians, in the range [-pi, pi].

Return type:

xarray.DataArray

Notes

To compute the angle phi we rely on the numpy.arctan2 function, which follows the C standard [1]. The C standard considers the case in which the inputs to the arctan2 [2] function are signed zeros [3]. For simplicity and interpretability, in movement we only consider the case of unsigned (positive) zeros. We implement it by setting the angle phi to 0 when the norm rho of the vector is 0.

References

See also

numpy.arctan2

Examples using cart2pol#

Compute head direction

Compute head direction