From ab7290a86595c2c3a440c2921200bb08413e9392 Mon Sep 17 00:00:00 2001
From: Tom MacWright <tom@macwright.org>
Date: Fri, 1 Feb 2013 11:31:31 -0500
Subject: [PATCH] Fix re-requesting failed tiles. Fixes #594

---
 js/id/renderer/background.js | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/js/id/renderer/background.js b/js/id/renderer/background.js
index 54e3835ee..cae44ca09 100644
--- a/js/id/renderer/background.js
+++ b/js/id/renderer/background.js
@@ -83,7 +83,10 @@ iD.Background = function() {
             }
         });
 
-        requests = uniqueBy(requests, 3);
+        requests = uniqueBy(requests, 3).filter(function(r) {
+            // don't re-request tiles which have failed in the past
+            return cache[r[3]] !== false;
+        });
 
         function load(d) {
             cache[d[3]] = true;
@@ -125,7 +128,7 @@ iD.Background = function() {
             .attr('src', function(d) { return d[3]; })
             .on('error', error)
             .on('load', load);
-        
+
         image.style(transformProp, imageTransform);
 
         if (Object.keys(cache).length > 100) cache = {};