From 2d987a3ece6113a3f6cbbeb1dbc8944519ce855c Mon Sep 17 00:00:00 2001
From: Bryan Housel <bryan@mapbox.com>
Date: Sat, 9 Apr 2016 23:04:02 -0400
Subject: [PATCH] Don't fetch overlay tiles or mapillary data around Null
 Island (closes #2751)

---
 js/id/renderer/tile_layer.js | 16 ++++++++++++++++
 js/id/services/mapillary.js  | 16 +++++++++++++++-
 2 files changed, 31 insertions(+), 1 deletion(-)

diff --git a/js/id/renderer/tile_layer.js b/js/id/renderer/tile_layer.js
index d0e0e8a33..11863e450 100644
--- a/js/id/renderer/tile_layer.js
+++ b/js/id/renderer/tile_layer.js
@@ -8,6 +8,19 @@ iD.TileLayer = function() {
         transformProp = iD.util.prefixCSSProperty('Transform'),
         source = d3.functor('');
 
+
+    // blacklist overlay tiles around Null Island..
+    function nearNullIsland(x, y, z) {
+        if (z >= 7) {
+            var center = Math.pow(2, z - 1),
+                width = Math.pow(2, z - 6),
+                min = center - (width / 2),
+                max = center + (width / 2) - 1;
+            return x >= min && x <= max && y >= min && y <= max;
+        }
+        return false;
+    }
+
     function tileSizeAtZoom(d, z) {
         var epsilon = 0.002;
         return ((tileSize * Math.pow(2, z - d[2])) / tileSize) + epsilon;
@@ -78,6 +91,9 @@ iD.TileLayer = function() {
             });
 
             requests = uniqueBy(requests, 3).filter(function(r) {
+                if (!!source.overlay && nearNullIsland(r[0], r[1], r[2])) {
+                    return false;
+                }
                 // don't re-request tiles which have failed in the past
                 return cache[r[3]] !== false;
             });
diff --git a/js/id/services/mapillary.js b/js/id/services/mapillary.js
index 87d96af94..231d2a943 100644
--- a/js/id/services/mapillary.js
+++ b/js/id/services/mapillary.js
@@ -36,6 +36,17 @@ iD.services.mapillary = function() {
         i.abort();
     }
 
+    function nearNullIsland(x, y, z) {
+        if (z >= 7) {
+            var center = Math.pow(2, z - 1),
+                width = Math.pow(2, z - 6),
+                min = center - (width / 2),
+                max = center + (width / 2) - 1;
+            return x >= min && x <= max && y >= min && y <= max;
+        }
+        return false;
+    }
+
     function getTiles(projection, dimensions) {
         var s = projection.scale() * 2 * Math.PI,
             z = Math.max(Math.log(s) / Math.log(2) - 8, 0),
@@ -64,7 +75,10 @@ iD.services.mapillary = function() {
 
 
     function loadTiles(which, url, projection, dimensions) {
-        var tiles = getTiles(projection, dimensions);
+        var tiles = getTiles(projection, dimensions).filter(function(t) {
+                var xyz = t.id.split(',');
+                return !nearNullIsland(xyz[0], xyz[1], xyz[2]);
+            });
 
         _.filter(which.inflight, function(v, k) {
             var wanted = _.find(tiles, function(tile) { return k === (tile.id + ',0'); });