Index: /issm/trunk-jpl/src/m/coordsystems/flaglatlongradius.m
===================================================================
--- /issm/trunk-jpl/src/m/coordsystems/flaglatlongradius.m	(revision 24817)
+++ /issm/trunk-jpl/src/m/coordsystems/flaglatlongradius.m	(revision 24817)
@@ -0,0 +1,16 @@
+function indices=flaglatlongradius(lat,long,lat0,long0,radius)
+%FLAGLATLONGRADIUS - given a vector of lat,long, and a circle of radius degrees around lat0,long0, 
+%                    return the indices into lat,long that are within this circle. 
+%                    lat and long should be between -90 and 90, and -180 and +180 respectively. 
+
+	distance=sqrt( (lat-lat0).^2+ (long-long0).^2);
+	
+	%three cases, depending on whether our circle goes past the -180 +180 longitude line: 
+	if (long0-radius)<=-180,
+		pos=find(long>0); long(pos)=long(pos)-360;
+	elseif (long0+radius)>=180,
+		pos=find(long<0); long(pos)=360+long(pos);
+	else
+	end
+	distance=sqrt( (lat-lat0).^2+ (long-long0).^2);
+	indices=find(distance<=radius);