diff --git a/code/pixel_array.h b/code/pixel_array.h
index 960210f..08984c5 100644
--- a/code/pixel_array.h
+++ b/code/pixel_array.h
@@ -42,8 +42,9 @@ template<typename Pixel> class PixelArray {
     delete [] mPixels;
   }
 
-  // A non-terrain value
-  static const Pixel EmptyPixel = -32738;  
+  // A non-terrain value; also don't overlap with peak or saddle
+  // indexes.
+  static const Pixel EmptyPixel = std::numeric_limits<Pixel>::min();  
 
   Pixel get(int x, int y) const {
     return mPixels[y * mWidth + x];