From 84a24dfa2176c3bb04fc0492d33ade1ba08de9f8 Mon Sep 17 00:00:00 2001
From: Andreas Specovius <andreas.specovius@fau.de>
Date: Tue, 16 Jun 2020 21:21:19 +0200
Subject: [PATCH] Fix in skycoord handling

---
 src/sky/GSkyRegionRect.cpp | 6 ++++++
 1 file changed, 6 insertions(+), 0 deletions(-)

diff --git a/src/sky/GSkyRegionRect.cpp b/src/sky/GSkyRegionRect.cpp
index 0dc1769..a969ab8 100644
--- a/src/sky/GSkyRegionRect.cpp
+++ b/src/sky/GSkyRegionRect.cpp
@@ -754,6 +754,7 @@ bool GSkyRegionRect::overlaps(const GSkyRegion& reg) const
 GSkyDir GSkyRegionRect::transform_to_local(const GSkyDir& skydir) const
 {
     // Get rid of negative right ascension coordinates
+    // to obtain angles in [0,2pi]
     // (Surely there is a more clever way to to this)
     double skydir_ra = skydir.ra();
     if (skydir_ra < 0) {
@@ -768,6 +769,11 @@ GSkyDir GSkyRegionRect::transform_to_local(const GSkyDir& skydir) const
     double dx = skydir_ra    - centre_ra;
     double dy = skydir.dec() - m_centre.dec();
 
+    // Make sure the closest angular separation is chosen
+    if (std::abs(dx) > gammalib::pi) {
+        dx = gammalib::twopi - std::abs(dx);
+    }
+
     // Correction for spherical coordinate system
     dx *= std::cos(skydir.dec());
 
--
libgit2 0.21.4