From 98da353c45557ae7697978621fca4ebd4d6a9463 Mon Sep 17 00:00:00 2001
From: Tom MacWright <tom@macwright.org>
Date: Thu, 15 Nov 2012 16:24:39 -0500
Subject: [PATCH] Round coordinates. Appears to improve performance, see #87
 and http://bl.ocks.org/4081356

---
 js/iD/renderer/Map.js | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/js/iD/renderer/Map.js b/js/iD/renderer/Map.js
index be9e9c23d..69f7af4d3 100755
--- a/js/iD/renderer/Map.js
+++ b/js/iD/renderer/Map.js
@@ -18,6 +18,13 @@ iD.Map = function(elem) {
         return { lon: o[0], lat: o[1] };
     }
 
+    function roundCoords(c) {
+        return [
+            Math.floor(c[0]),
+            Math.floor(c[1])
+        ];
+    }
+
     var map = {},
         width, height,
         dispatch = d3.dispatch('move', 'update'),
@@ -48,7 +55,7 @@ iD.Map = function(elem) {
             })
             .on('dragend', map.update),
         nodeline = function(d) {
-            return 'M' + d.nodes.map(ll2a).map(projection).join('L');
+            return 'M' + d.nodes.map(ll2a).map(projection).map(roundCoords).join('L');
         },
         key = function(d) { return d.id; };