X-Git-Url: http://pileus.org/git/?a=blobdiff_plain;f=src%2Fgis-util.c;h=c25b57c4ed0116902b7a06457d60a76011ab401c;hb=aa0783b3ce8ab7dd72560b7327600c2b36a8b391;hp=3bd5246002e134843c7c8c2a13726dbc8e05c653;hpb=a2a902d978b6050289f7a92794fb1dc0aa2b5e26;p=grits

diff --git a/src/gis-util.c b/src/gis-util.c
index 3bd5246..c25b57c 100644
--- a/src/gis-util.c
+++ b/src/gis-util.c
@@ -1,5 +1,5 @@
 /*
- * Copyright (C) 2009 Andy Spencer <spenceal@rose-hulman.edu>
+ * Copyright (C) 2009-2010 Andy Spencer <andy753421@gmail.com>
  *
  * This program is free software: you can redistribute it and/or modify
  * it under the terms of the GNU General Public License as published by
@@ -65,3 +65,16 @@ gdouble distd(gdouble *a, gdouble *b)
 	            (a[1]-b[1])*(a[1]-b[1]) +
 	            (a[2]-b[2])*(a[2]-b[2]));
 }
+
+gdouble lon_avg(gdouble a, gdouble b)
+{
+	gdouble diff = ABS(a-b);
+	gdouble avg  = (a+b)/2;
+	if (diff > 180) {
+		if (avg >= 0)
+			avg -= 180;
+		else
+			avg += 180;
+	}
+	return avg;
+}