From 8a0ff95f709358e1c22b6e8ae00b2cffc4723a43 Mon Sep 17 00:00:00 2001
From: Jan David Mol <mol@astron.nl>
Date: Thu, 7 Feb 2013 12:49:17 +0000
Subject: [PATCH] Task #3916: Added cos(dec) correction to ra for tied-array
rings, to properly map the tied-array rings on the non-linear radec
coordinate system.
---
RTCP/Run/src/LOFAR/Parset.py | 4 +++-
RTCP/Run/src/LOFAR/RingCoordinates.py | 23 ++++++++++++++++++++---
2 files changed, 23 insertions(+), 4 deletions(-)
diff --git a/RTCP/Run/src/LOFAR/Parset.py b/RTCP/Run/src/LOFAR/Parset.py
index 8a3ac9e36ff..de3445852ba 100644
--- a/RTCP/Run/src/LOFAR/Parset.py
+++ b/RTCP/Run/src/LOFAR/Parset.py
@@ -202,11 +202,13 @@ class Parset(util.Parset.Parset):
self.setdefault("Observation.Beam[%s].tabRingSize" % (b,),0.0)
dirtype = self["Observation.Beam[%s].directionType" % (b,)]
+ center_angle1 = float(self["Observation.Beam[%s].angle1" % (b,)])
+ center_angle2 = float(self["Observation.Beam[%s].angle2" % (b,)])
dm = int(self.get("OLAP.dispersionMeasure",0))
nrrings = int(self["Observation.Beam[%s].nrTabRings" % (b,)])
width = float(self["Observation.Beam[%s].tabRingSize" % (b,)])
- ringcoordinates = RingCoordinates( nrrings, width )
+ ringcoordinates = RingCoordinates( nrrings, width, (center_angle1, center_angle2), dirtype )
ringset = [
{ "angle1": angle1,
"angle2": angle2,
diff --git a/RTCP/Run/src/LOFAR/RingCoordinates.py b/RTCP/Run/src/LOFAR/RingCoordinates.py
index fc82d772aea..02e52a3c2d1 100644
--- a/RTCP/Run/src/LOFAR/RingCoordinates.py
+++ b/RTCP/Run/src/LOFAR/RingCoordinates.py
@@ -1,11 +1,28 @@
#!/usr/bin/python
-from math import sqrt
+from math import sqrt, cos, pi
class RingCoordinates:
- def __init__(self, numrings, width):
+ def __init__(self, numrings, width, center, dirtype):
self.numrings = numrings
self.width = width
+ self.center = center
+ self.dirtype = dirtype
+
+ def cos_adjust(self, offset):
+ if dirtype != "J2000" and dirtype != "B1950":
+ return offset
+
+ # warp coordinates closer to the NCP
+
+ cos_dec = cos(self.center[1] + offset[1])
+ epsilon = 0.0001
+
+ if cos_dec > epsilon:
+ return (offset[0]/cos_dec, offset[1])
+ else:
+ return offset
+
def len_edge(self):
"""
@@ -120,5 +137,5 @@ class RingCoordinates:
l += dl[side]
m += dm[side]
- return coordinates
+ return map(self.cos_adjust, coordinates)
--
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