def getstepoffset(offset,coord):
"""Get stepdec and declabel given the range in declination plotted"""
# label steps in arcseconds
offlabel = array([1 ,5,10,15,20,30,60,300,600,900,1200,1800,3600,18000,36000])
offstep = array([0.5,1, 5, 5, 5,10,20, 60,300,300, 300, 600,1200, 3600,18000])
tmp = abs(offset[1] - offset[0])
if coord == 'so': # arcsecond offset
tmp = 3600*tmp
elif coord == 'mo': # arcminute offset
offlabel = offlabel/60.
offstep = offsetep/60.
tmp = 60*tmp
elif coord == 'do': # degree offset
offlabel = offlabel/3600.
offstep = offstep/3600.
else:
nlclib.error("getstepoffset(): coord keyword must be one of: so, mo, do!")
guess = tmp/6. # aim for about 6 labels
diff = [abs(guess-a) for a in offlabel]
idx = diff.index(min(diff))
return offstep[idx],offlabel[idx]
def getstepdec(dec): """Get stepdec and declabel given the range in declination plotted""" # label steps in arcseconds tmplabel = [1 ,5,10,15,20,30,60,300,600,900,1200,1800,3600,18000,36000] tmpstep = [0.5,1, 5, 5, 5,10,20, 60,300,300, 300, 600,1200, 3600,18000] declabel = map(lambda a: a/3600.,tmplabel) # convert to degrees stepdec = map(lambda a: a/3600.,tmpstep) # convert to degrees tmp = abs(dec[1] - dec[0]) guess = tmp/6. # aim for about 6 labels diff = [abs(guess-a) for a in declabel] idx = diff.index(min(diff)) return stepdec[idx],declabel[idx]
def getstepra(ra):
"""Get stepra and ralabel for the range of RA plotted.
Input ra is two values in degrees"""
# label steps in hour-seconds
tmplabel = [1 , 2,5,10,15,20,30,60,120,300,600,900,1200,1800,3600,18000]
tmpstep = [0.5,0.5,1, 2, 5, 5, 5,20, 30, 60,300,300, 300, 600,1200, 3600]
ralabel = map(lambda a: a/240.,tmplabel) # convert to degrees
stepra = map(lambda a: a/240.,tmpstep) # convert to degrees
tmp = abs(ra[1] - ra[0])
guess = tmp/6. # aim for about 6 labels
diff = [abs(guess-a) for a in ralabel]
idx = diff.index(min(diff))
return stepra[idx],ralabel[idx]