Source code for psychopy.tools.coordinatetools

#!/usr/bin/env python
# -*- coding: utf-8 -*-

# Part of the PsychoPy library
# Copyright (C) 2002-2018 Jonathan Peirce (C) 2019-2021 Open Science Tools Ltd.
# Distributed under the terms of the GNU General Public License (GPL).

"""Functions and classes related to coordinate system conversion
"""
from __future__ import absolute_import, division, print_function

from past.utils import old_div
import numpy
from numpy import radians


[docs]def cart2pol(x, y, units='deg'): """Convert from cartesian to polar coordinates. :usage: theta, radius = cart2pol(x, y, units='deg') units refers to the units (rad or deg) for theta that should be returned """ radius = numpy.hypot(x, y) theta = numpy.arctan2(y, x) if units in ('deg', 'degs'): theta = theta * 180 / numpy.pi return theta, radius
[docs]def pol2cart(theta, radius, units='deg'): """Convert from polar to cartesian coordinates. usage:: x,y = pol2cart(theta, radius, units='deg') """ if units in ('deg', 'degs'): theta = theta * numpy.pi / 180.0 xx = radius * numpy.cos(theta) yy = radius * numpy.sin(theta) return xx, yy
[docs]def cart2sph(z, y, x): """Convert from cartesian coordinates (x,y,z) to spherical (elevation, azimuth, radius). Output is in degrees. usage: array3xN[el,az,rad] = cart2sph(array3xN[x,y,z]) OR elevation, azimuth, radius = cart2sph(x,y,z) If working in DKL space, z = Luminance, y = S and x = LM """ width = len(z) elevation = numpy.empty([width, width]) radius = numpy.empty([width, width]) azimuth = numpy.empty([width, width]) radius = numpy.sqrt(x**2 + y**2 + z**2) azimuth = numpy.arctan2(y, x) # Calculating the elevation from x,y up elevation = numpy.arctan2(z, numpy.sqrt(x**2 + y**2)) # convert azimuth and elevation angles into degrees azimuth *= (old_div(180.0, numpy.pi)) elevation *= (old_div(180.0, numpy.pi)) sphere = numpy.array([elevation, azimuth, radius]) sphere = numpy.rollaxis(sphere, 0, 3) return sphere
[docs]def sph2cart(*args): """Convert from spherical coordinates (elevation, azimuth, radius) to cartesian (x,y,z). usage: array3xN[x,y,z] = sph2cart(array3xN[el,az,rad]) OR x,y,z = sph2cart(elev, azim, radius) """ if len(args) == 1: # received an Nx3 array elev = args[0][0, :] azim = args[0][1, :] radius = args[0][2, :] returnAsArray = True elif len(args) == 3: elev = args[0] azim = args[1] radius = args[2] returnAsArray = False z = radius * numpy.sin(radians(elev)) x = radius * numpy.cos(radians(elev)) * numpy.cos(radians(azim)) y = radius * numpy.cos(radians(elev)) * numpy.sin(radians(azim)) if returnAsArray: return numpy.asarray([x, y, z]) else: return x, y, z

Back to top