diff --git a/data/index.js b/data/index.js
index 92cd0a335..0423aa9b4 100644
--- a/data/index.js
+++ b/data/index.js
@@ -1,3 +1,5 @@
+import _values from 'lodash-es/values';
+
 export { wikipedia as dataWikipedia } from 'wmf-sitematrix';
 export { default as dataSuggestions } from 'name-suggestion-index/name-suggestions.json';
 
@@ -24,31 +26,31 @@ import { categories } from './presets/categories.json';
 import { fields } from './presets/fields.json';
 
 import { geoArea as d3_geoArea } from 'd3-geo';
-import _values from 'lodash-es/values';
 import whichPolygon from 'which-polygon';
 
-var features = _values(ociFeatures).map(function(feature) {
-    // workaround for which-polygon
-    // only supports `properties`, not `id`
+
+// index the osm-community-index
+var ociFeatureCollection = _values(ociFeatures).map(function(feature) {
+    // workaround for which-polygon: only supports `properties`, not `id`
     // https://github.com/mapbox/which-polygon/pull/6
     feature.properties = {
         id: feature.id,
         area: d3_geoArea(feature)   // also precompute areas
     };
-
     return feature;
 });
 
+
 export var data = {
     community: {
         features: ociFeatures,
         resources: ociResources,
         query: whichPolygon({
             type: 'FeatureCollection',
-            features: features
+            features: ociFeatureCollection
         })
     },
-    imagery: dataImagery,
+    imagery: dataImagery,  //legacy
     presets: {
         presets: presets,
         defaults: defaults,
diff --git a/modules/renderer/background.js b/modules/renderer/background.js
index 644986cad..71325195f 100644
--- a/modules/renderer/background.js
+++ b/modules/renderer/background.js
@@ -1,9 +1,12 @@
 import _find from 'lodash-es/find';
+import _omit from 'lodash-es/omit';
 
 import { dispatch as d3_dispatch } from 'd3-dispatch';
 import { interpolateNumber as d3_interpolateNumber } from 'd3-interpolate';
 import { select as d3_select } from 'd3-selection';
 
+import whichPolygon from 'which-polygon';
+
 import { data } from '../../data';
 import { geoExtent, geoMetersToOffset, geoOffsetToMeters} from '../geo';
 import { rendererBackgroundSource } from './background_source';
@@ -209,18 +212,24 @@ export function rendererBackground(context) {
 
 
     background.sources = function(extent) {
+        if (!data.imagery || !data.imagery.query) return [];   // called before init()?
+
+        var matchIDs = {};
+        var matchImagery = data.imagery.query.bbox(extent.rectangle(), true) || [];
+        matchImagery.forEach(function(d) { matchIDs[d.id] = true; });
+
         return _backgroundSources.filter(function(source) {
-            return source.intersects(extent);
+            return matchIDs[source.id];
         });
     };
 
 
-    background.dimensions = function(_) {
-        if (!_) return;
-        baseLayer.dimensions(_);
+    background.dimensions = function(d) {
+        if (!d) return;
+        baseLayer.dimensions(d);
 
         _overlayLayers.forEach(function(layer) {
-            layer.dimensions(_);
+            layer.dimensions(d);
         });
     };
 
@@ -366,15 +375,39 @@ export function rendererBackground(context) {
             return geoExtent([args[2], args[1]]);
         }
 
-        var dataImagery = data.imagery || [];
         var q = utilStringQs(window.location.hash.substring(1));
         var requested = q.background || q.layer;
         var extent = parseMap(q.map);
         var first;
         var best;
 
+
+        data.imagery = data.imagery || [];
+        data.imagery.features = {};
+
+        // build efficient index and querying for data.imagery
+        var world = [[[-180, -90], [-180, 90], [180, 90], [180, -90], [-180, -90]]];
+        var features = data.imagery.map(function(source) {
+            var feature = {
+                type: 'Feature',
+                id: source.id,
+                properties: _omit(source, ['polygon']),
+                geometry: {
+                    type: 'MultiPolygon',
+                    coordinates: [ source.polygon || world ]
+                }
+            };
+            data.imagery.features[source.id] = feature;
+            return feature;
+        });
+        data.imagery.query = whichPolygon({
+            type: 'FeatureCollection',
+            features: features
+        });
+
+
         // Add all the available imagery sources
-        _backgroundSources = dataImagery.map(function(source) {
+        _backgroundSources = data.imagery.map(function(source) {
             if (source.type === 'bing') {
                 return rendererBackgroundSource.Bing(source, dispatch);
             } else if (/^EsriWorldImagery/.test(source.id)) {
diff --git a/modules/renderer/background_source.js b/modules/renderer/background_source.js
index fc8f07967..f3e2d5014 100644
--- a/modules/renderer/background_source.js
+++ b/modules/renderer/background_source.js
@@ -9,13 +9,7 @@ import {
 import { json as d3_json } from 'd3-request';
 
 import { t } from '../util/locale';
-
-import {
-    geoExtent,
-    geoPolygonIntersectsPolygon,
-    geoSphericalDistance
-} from '../geo';
-
+import { geoExtent, geoSphericalDistance } from '../geo';
 import { utilDetect } from '../util/detect';
 
 
@@ -116,7 +110,7 @@ export function rendererBackgroundSource(data) {
                 var lat = Math.atan(sinh(Math.PI * (1 - 2 * y / zoomSize)));
 
                 switch (this.projection) {
-                    case 'EPSG:4326': // todo: alternative codes of WGS 84?
+                    case 'EPSG:4326':
                         return {
                             x: lon * 180 / Math.PI,
                             y: lat * 180 / Math.PI
@@ -162,14 +156,6 @@ export function rendererBackgroundSource(data) {
     };
 
 
-    source.intersects = function(extent) {
-        extent = extent.polygon();
-        return !data.polygon || data.polygon.some(function(polygon) {
-            return geoPolygonIntersectsPolygon(polygon, extent, true);
-        });
-    };
-
-
     source.validZoom = function(z) {
         return source.zoomExtent[0] <= z &&
             (source.overzoom || source.zoomExtent[1] > z);
diff --git a/modules/svg/debug.js b/modules/svg/debug.js
index 26e6e112e..8476991ff 100644
--- a/modules/svg/debug.js
+++ b/modules/svg/debug.js
@@ -2,22 +2,12 @@ import _values from 'lodash-es/values';
 
 import { select as d3_select } from 'd3-selection';
 
-import { geoPolygonIntersectsPolygon } from '../geo';
 import { data, dataImperial, dataDriveLeft } from '../../data';
 import { svgPath } from './index';
 
 
 export function svgDebug(projection, context) {
 
-    function multipolygons(imagery) {
-        return imagery.map(function(data) {
-            return {
-                type: 'MultiPolygon',
-                coordinates: [ data.polygon ]
-            };
-        });
-    }
-
     function drawDebug(selection) {
         var showsTile = context.getDebug('tile');
         var showsCollision = context.getDebug('collision');
@@ -89,16 +79,11 @@ export function svgDebug(projection, context) {
 
 
         var extent = context.map().extent();
-        var dataImagery = data.imagery || [];
-        var availableImagery = showsImagery && multipolygons(dataImagery.filter(function(source) {
-            if (!source.polygon) return false;
-            return source.polygon.some(function(polygon) {
-                return geoPolygonIntersectsPolygon(polygon, extent, true);
-            });
-        }));
+        var matchImagery = (showsImagery && data.imagery.query.bbox(extent.rectangle(), true)) || [];
+        var features = matchImagery.map(function(d) { return data.imagery.features[d.id]; });
 
         var imagery = layer.selectAll('path.debug-imagery')
-            .data(showsImagery ? availableImagery : []);
+            .data(features);
 
         imagery.exit()
             .remove();