def angdist2pixdist(self, img, angdist, pa, location=None):
"""Returns the distance in pixels for a given angular distance in degrees
pa - position angle in degrees east of north
location - x and y location of center
"""
import functions as func
if location is None:
x1 = int(img.image_arr.shape[2] / 2.0)
y1 = int(img.image_arr.shape[3] / 2.0)
else:
x1, y1 = location
pa_pix = self.get_rot(img, location)
x0 = x1 - 10.0 * N.sin((pa + pa_pix) * N.pi / 180.0)
y0 = y1 - 10.0 * N.cos((pa + pa_pix) * N.pi / 180.0)
ra0, dec0 = img.pix2sky([x0, y0])
x2 = x1 + 10.0 * N.sin((pa + pa_pix) * N.pi / 180.0)
y2 = y1 + 10.0 * N.cos((pa + pa_pix) * N.pi / 180.0)
ra2, dec2 = img.pix2sky([x2, y2])
angdist12 = func.angsep(ra0, dec0, ra2, dec2) # degrees
pixdist12 = N.sqrt((x0 - x2)**2 + (y0 - y2)**2) # pixels
if angdist12 > 0.0:
result = angdist * pixdist12 / angdist12
if N.isnan(result) or result <= 0.0:
result = N.mean(img.wcs_obj.acdelt[0:2])
else:
result = N.mean(img.wcs_obj.acdelt[0:2])
return result
def angdist2pixdist(self, img, angdist, pa, location=None):
"""Returns the distance in pixels for a given angular distance in degrees
pa - position angle in degrees east of north
location - x and y location of center
"""
import functions as func
if location is None:
x1 = int(img.image_arr.shape[2] / 2.0)
y1 = int(img.image_arr.shape[3] / 2.0)
else:
x1, y1 = location
pa_pix = self.get_rot(img, location)
x0 = x1 - 10.0 * N.sin( (pa + pa_pix) * N.pi / 180.0 )
y0 = y1 - 10.0 * N.cos( (pa + pa_pix) * N.pi / 180.0 )
ra0, dec0 = img.pix2sky([x0, y0])
x2 = x1 + 10.0 * N.sin( (pa + pa_pix) * N.pi / 180.0 )
y2 = y1 + 10.0 * N.cos( (pa + pa_pix) * N.pi / 180.0 )
ra2, dec2 = img.pix2sky([x2, y2])
angdist12 = func.angsep(ra0, dec0, ra2, dec2) # degrees
pixdist12 = N.sqrt( (x0 - x2)**2 + (y0 - y2)**2 ) # pixels
if angdist12 > 0.0:
result = angdist * pixdist12 / angdist12
if N.isnan(result) or result <= 0.0:
result = N.mean(img.wcs_obj.acdelt[0:2])
else:
result = N.mean(img.wcs_obj.acdelt[0:2])
return result
def pixdist2angdist(self, img, pixdist, pa, location=None):
"""Returns the angular distance in degrees for a given distance in pixels
pa - position angle in degrees CCW from +y axis
location - x and y location of center
"""
import functions as func
if location is None:
x1 = int(img.image_arr.shape[2] / 2.0)
y1 = int(img.image_arr.shape[3] / 2.0)
else:
x1, y1 = location
x0 = x1 - pixdist / 2.0 * N.sin(pa * N.pi / 180.0)
y0 = y1 - pixdist / 2.0 * N.cos(pa * N.pi / 180.0)
ra0, dec0 = img.pix2sky([x0, y0])
x2 = x1 + pixdist / 2.0 * N.sin(pa * N.pi / 180.0)
y2 = y1 + pixdist / 2.0 * N.cos(pa * N.pi / 180.0)
ra2, dec2 = img.pix2sky([x2, y2])
angdist12 = func.angsep(ra0, dec0, ra2, dec2) # degrees
return angdist12
def pixdist2angdist(self, img, pixdist, pa, location=None):
"""Returns the angular distance in degrees for a given distance in pixels
pa - position angle in degrees CCW from +y axis
location - x and y location of center
"""
import functions as func
if location is None:
x1 = int(img.image_arr.shape[2] / 2.0)
y1 = int(img.image_arr.shape[3] / 2.0)
else:
x1, y1 = location
x0 = x1 - pixdist / 2.0 * N.sin(pa * N.pi / 180.0)
y0 = y1 - pixdist / 2.0 * N.cos(pa * N.pi / 180.0)
ra0, dec0 = img.pix2sky([x0, y0])
x2 = x1 + pixdist / 2.0 * N.sin(pa * N.pi / 180.0)
y2 = y1 + pixdist / 2.0 * N.cos(pa * N.pi / 180.0)
ra2, dec2 = img.pix2sky([x2, y2])
angdist12 = func.angsep(ra0, dec0, ra2, dec2) # degrees
return angdist12