WCS User Tools¶
grid_from_bounding_box is a function which returns a grid of input points based on the bounding_box of the WCS.
>>> from gwcs.wcstools import grid_from_bounding_box >>> bounding_box = ((0, 4096), (0, 2048)) >>> x, y = grid_from_bounding_box(bounding_box) >>> ra, dec = w(x, y)
wcstools module contains functions of general usability.
wcs_from_fiducial is a function which given a fiducial in some coordinate system,
returns a WCS object.
>>> from gwcs.wcstools import wcs_from_fiducial >>> from astropy import coordinates as coord >>> from astropy import units as u >>> from astropy.modeling import models
- To create a WCS from a pointing on the sky, as a minimum pass a sky coordinate and a projection to the function.
>>> fiducial = coord.SkyCoord(5.46 * u.deg, -72.2 * u.deg, frame='icrs') >>> tan = models.Pix2Sky_TAN()
Any additional transforms are prepended to the projection and sky rotation.
>>> trans = models.Shift(-2048) & models.Shift(-1024) | models.Scale(1.38*10**-5) & models.Scale(1.38*10**-5) >>> w = wcs_from_fiducial(fiducial, projection=tan, transform=trans) >>> w(2048, 1024) (5.46, -72.2)