new tools for handling SDSS mask

mytools/contour_pixels.cpp

@@ -0,0 +1,47 @@
+#include <vector>
+#include <healpix_map.h>
+#include <healpix_map_fitsio.h>
+#include "contour_pixels.hpp"
+
+using namespace std;
+
+static const bool DEBUG = true;
+
+void computeContourPixels(Healpix_Map<float>& m, vector<int> contour)
+{
+  for (int p = 0; p < m.Npix(); p++)
+    {
+      fix_arr<int, 8> result;
+
+      m.neighbors(p, result);
+      for (int q = 0; q < 8; q++)
+	{
+	  if (result[q] < 0)
+	    continue;
+
+	  delta = (m[p]-0.5)*(m[result[q]]-0.5);
+	  if (delta < 0)
+	    {
+	      contour.push_back(p);
+	      // This is boundary go to next pixel
+	      break;
+	    }
+	}      
+    }
+
+  if (DEBUG)
+    {
+      Healpix_Map<int> contour_map;
+
+      contour_map.SetNside(RING, m.Nside());
+      contour_map.fill(0);
+      for (int p = 0; p < contour.size(); p++)
+	{
+	  contour_map[contour[p]]=1;
+	}
+
+      fitshandle h;
+      h.create("!contour_map.fits");
+      write_Healpix_map_to_fits(h, contour_map, planckType<int>());
+    }
+}