Source code for lenstronomy.Data.coord_transforms

import numpy.linalg as linalg
import numpy as np
import lenstronomy.Util.util as util

from lenstronomy.Util.package_util import exporter
export, __all__ = exporter()


[docs]@export class Coordinates(object): """ class to handle linear coordinate transformations of a square pixel image """ def __init__(self, transform_pix2angle, ra_at_xy_0, dec_at_xy_0): """ initialize the coordinate-to-pixel transform and their inverse :param transform_pix2angle: 2x2 matrix, mapping of pixel to coordinate :param ra_at_xy_0: ra coordinate at pixel (0,0) :param dec_at_xy_0: dec coordinate at pixel (0,0) """ self._Mpix2a = transform_pix2angle self._Ma2pix = linalg.inv(self._Mpix2a) self._ra_at_xy_0 = ra_at_xy_0 self._dec_at_xy_0 = dec_at_xy_0 self._x_at_radec_0, self._y_at_radec_0 = util.map_coord2pix(-self._ra_at_xy_0, -self._dec_at_xy_0, 0, 0, self._Ma2pix) @property def transform_angle2pix(self): """ :return: transformation matrix from angular to pixel coordinates """ return self._Ma2pix @property def transform_pix2angle(self): """ :return: transformation matrix from pixel to angular coordinates """ return self._Mpix2a @property def xy_at_radec_0(self): """ :return: pixel coordinate at angular (0,0) point """ return self._x_at_radec_0, self._y_at_radec_0 @property def radec_at_xy_0(self): """ :return: RA, DEC coordinate at (0,0) pixel coordinate """ return self._ra_at_xy_0, self._dec_at_xy_0
[docs] def map_coord2pix(self, ra, dec): """ maps the (ra,dec) coordinates of the system into the pixel coordinate of the image :param ra: relative RA coordinate as defined by the coordinate frame :param dec: relative DEC coordinate as defined by the coordinate frame :return: (x, y) pixel coordinates """ return util.map_coord2pix(ra, dec, self._x_at_radec_0, self._y_at_radec_0, self._Ma2pix)
[docs] def map_pix2coord(self, x, y): """ maps the (x,y) pixel coordinates of the image into the system coordinates :param x: pixel coordinate (can be 1d numpy array), defined in the center of the pixel :param y: pixel coordinate (can be 1d numpy array), defined in the center of the pixel :return: relative (RA, DEC) coordinates of the system """ return util.map_coord2pix(x, y, self._ra_at_xy_0, self._dec_at_xy_0, self._Mpix2a)
@property def pixel_area(self): """ angular area of a pixel in the image :return: area [arcsec^2] """ return np.abs(linalg.det(self._Mpix2a)) @property def pixel_width(self): """ size of pixel :return: sqrt(pixel_area) """ return np.sqrt(self.pixel_area)
[docs] def coordinate_grid(self, nx, ny): """ :param nx: number of pixels in x-direction :param ny: number of pixels in y-direction :return: 2d arrays with coordinates in RA/DEC with ra_coord[y-axis, x-axis] """ ra_coords, dec_coords = util.grid_from_coordinate_transform(nx, ny, self._Mpix2a, self._ra_at_xy_0, self._dec_at_xy_0) ra_coords = util.array2image(ra_coords, nx, ny) # new dec_coords = util.array2image(dec_coords, nx, ny) # new return ra_coords, dec_coords
[docs] def shift_coordinate_system(self, x_shift, y_shift, pixel_unit=False): """ shifts the coordinate system :param x_shift: shift in x (or RA) :param y_shift: shift in y (or DEC) :param pixel_unit: bool, if True, units of pixels in input, otherwise RA/DEC :return: updated data class with change in coordinate system """ self._shift_coordinates(x_shift, y_shift, pixel_unit)
def _shift_coordinates(self, x_shift, y_shift, pixel_unit=False): """ shifts the coordinate system :param x_shift: shift in x (or RA) :param y_shift: shift in y (or DEC) :param pixel_unit: bool, if True, units of pixels in input, otherwise RA/DEC :return: updated data class with change in coordinate system """ if pixel_unit is True: ra_shift, dec_shift = self.map_pix2coord(x_shift, y_shift) ra_shift -= self._ra_at_xy_0 dec_shift -= self._dec_at_xy_0 print(ra_shift, dec_shift, 'test') else: ra_shift, dec_shift = x_shift, y_shift self._ra_at_xy_0 += ra_shift self._dec_at_xy_0 += dec_shift self._x_at_radec_0, self._y_at_radec_0 = util.map_coord2pix(-self._ra_at_xy_0, -self._dec_at_xy_0, 0, 0, self._Ma2pix)
[docs]@export class Coordinates1D(Coordinates): """ coordinate grid described in 1-d arrays """
[docs] def coordinate_grid(self, nx, ny): """ :param nx: number of pixels in x-direction :param ny: number of pixels in y-direction :return: 2d arrays with coordinates in RA/DEC with ra_coord[y-axis, x-axis] """ ra_coords, dec_coords = util.grid_from_coordinate_transform(nx, ny, self._Mpix2a, self._ra_at_xy_0, self._dec_at_xy_0) return ra_coords, dec_coords