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# This file is part of the Astrometry.net suite.
# Licensed under a 3-clause BSD style license - see LICENSE
import math
try:
import pyfits
except ImportError:
try:
from astropy.io import fits as pyfits
except ImportError:
raise ImportError("Cannot import either pyfits or astropy.io.fits")
from numpy import *
from matplotlib.pylab import figure, plot, xlabel, ylabel, loglog, clf
from matplotlib.pylab import semilogy, show, find, legend, hist, axis
def plotDvsR(ix, iy, fx, fy, R):
IR = argsort(R)
mR = []
mD = []
mI = []
# Look at index stars in order of R.
for ii in range(len(IR)):
i = IR[ii]
x = ix[i]
y = iy[i]
D = sqrt((fx - x)**2 + (fy - y)**2)
# Grab field stars within a matching radius.
r = 5
I = find( D < r )
for j in I:
mR.append(R[i])
mD.append(D[j])
mI.append(ii)
plot(mR, mD, 'ro')
xlabel('Distance from quad center')
ylabel('Match distance')
def plotIvsR(ix, iy, fx, fy, cx, cy):
RF = sqrt((fx - cx)**2 + (fy - cy)**2)
mD2 = []
mI2 = []
for i in range(len(RF)):
r = 5
D = sqrt((ix - fx[i])**2 + (iy - fy[i])**2)
I = find( D < r )
for j in I:
mD2.append(D[j])
mI2.append(i)
#plot(mI, mD, 'ro', mI2, mD2, 'bo')
plot(mI2, mD2, 'bo')
xlabel('Index star number')
ylabel('Match distance')
#legend(('Sorted by dist from quad center', 'Sorted by brightness'))
if __name__ == '__main__':
# Index stars
ixy = pyfits.open('ver/index.xy.fits')
ixy = ixy[1].data
ix = ixy.field(0)
iy = ixy.field(1)
NI = len(ix)
# Field stars
fxy = pyfits.open('ver/field.xy.fits')
fxy = fxy[1].data
fx = fxy.field(0)
fy = fxy.field(1)
NF = len(fx)
# The matched quad.
mf = pyfits.open('ver/match.fits')
mf = mf[1].data
quad = mf.field('quadpix')[0]
quad = quad[0:8].reshape(4,2)
qx = quad[:,0]
qy = quad[:,1]
# Quad center.
cx = mean(qx)
cy = mean(qy)
# Grab index stars that are within the field.
iok = find( (ix > min(fx)) *
(ix < max(fx)) *
(iy > min(fy)) *
(iy < max(fy)) )
ix = [ix[i] for i in iok]
iy = [iy[i] for i in iok]
figure(1)
clf()
I = [0, 2, 1, 3, 0]
plot(
[cx], [cy], 'ro',
qx[I], qy[I], 'r-',
ix, iy, 'rx',
fx, fy, 'b+',
)
# RMS quad radius
RQ = sqrt(sum((qx - cx)**2 + (qy - cy)**2) / 4)
# Distance from quad center.
RI = sqrt((ix - cx)**2 + (iy - cy)**2)
RF = sqrt((fx - cx)**2 + (fy - cy)**2)
# Angle from quad center.
AI = array([math.atan2(y - cy, x - cx) for (x,y) in zip(ix,iy)])
AF = array([math.atan2(y - cy, x - cx) for (x,y) in zip(fx,fy)])
# Look at index stars in order of R.
IR = argsort(RI)
allD = array([])
allDR = array([])
allDA = array([])
allR = array([])
allDist = array([])
for i in IR:
# regularizer...
reg = RQ
#
Distscale = 1
DRscale = 1 / RQ
dR = ((RI[i] + reg) / (RF + reg)) - 1.0
dA = AI[i] - AF
# handle wrap-around
absdA = abs(dA)
absdA = vstack((absdA, abs(absdA - 2*math.pi))).min(axis=0)
#D = sqrt(dR**2 + dA**2)
D = sqrt(dR**2 + absdA**2)
D = D / DRscale
Dist = sqrt((ix[i] - fx)**2 + (iy[i] - fy)**2)
Dist = Dist / Distscale
iSmall = array(find((D < 1) + (Dist < 1)))
allD = hstack((allD, D[iSmall]))
allDR = hstack((allDR, dR[iSmall]))
allDA = hstack((allDA, dA[iSmall]))
allR = hstack((allR, repeat(RI[i], len(iSmall))))
allDist = hstack((allDist, Dist[iSmall]))
figure(2)
clf()
plot(allDR, allDA, 'ro', ms=1)
xlabel('DR')
ylabel('DA')
figure(3)
clf()
#plot(allR/RQ, allD, 'r.')
#plot(allR/RQ, vstack((allD, allDist)).min(axis=0), 'r.')
plot(
#allR/RQ, vstack((allD, allDist)).min(axis=0), 'mo',
allR/RQ, allD, 'r+',
allR/RQ, allDist, 'bx'
)
xlabel('R (quad radiuses)')
#ylabel('min( Dist, D(R+A) )')
ylabel('Dist, D(R,A)')
a = axis()
axis([a[0], a[1], 0, 2.0])
legend(('D(R,A)', 'D'))
#allDist = array([])
#allRDist = array([])
#for i in IR:
# Dist = sqrt((ix[i] - fx)**2 + (iy[i] - fy)**2)
# iSmall = array(find(Dist < 5))
# allDist = hstack((allDist, Dist[iSmall]))
# allRDist = hstack((allRDist, repeat(RI[i], len(iSmall))))
#figure(4)
#clf()
#plot(allRDist/RQ, allDist, 'r.')
#xlabel('R')
#ylabel('Dist')
#figure(2)
#clf()
#plotDvsR(ix, iy, RI, fx, fy)
#figure(3)
#clf()
#plotDvsI(ix, iy, fx, fy, cx, cy)
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