diff --git a/src/layer.js b/src/layer.js
index 907a68edce..c949f7e5a5 100644
--- a/src/layer.js
+++ b/src/layer.js
@@ -17,14 +17,17 @@ var rendererForAnnotations = require('./registry').rendererForAnnotations;
  *   to determine the renderer.  If a {@link geo.renderer} instance, the
  *   renderer is not recreated; not all renderers can be shared by multiple
  *   layers.
- * @property {boolean} [autoshareRenderer=true] If truthy and the renderer
- *   supports it, auto-share renderers between layers.  Currently, auto-sharing
- *   can only occur for webgl renderers, and will only occur between adjacent
- *   layers than have the same opacity.  Shared renderers has slightly
- *   different behavior than non-shared renderers: changing z-index may result
- *   in rerendering and be slightly slower; only one DOM canvas is used for all
- *   shared renderers.  Some features have slight z-stacking differences in
- *   shared versus non-shared renderers.
+ * @property {boolean|string} [autoshareRenderer=true] If truthy and the
+ *   renderer supports it, auto-share renderers between layers.  Currently,
+ *   auto-sharing can only occur for webgl renderers and adjacent layers.  If
+ *   `true`, sharing will only occur if the layers have the same opacity and it
+ *   is 1 or 0 and any tile layers are below non-tile layers.  If `"more"`,
+ *   sharing will occur for any adjacent layers that have the same opacity.
+ *   Shared renderers has slightly different behavior than non-shared
+ *   renderers: changing z-index may result in rerendering and be slightly
+ *   slower; only one DOM canvas is used for all shared renderers.  Some
+ *   features have slight z-stacking differences in shared versus non-shared
+ *   renderers.
  * @property {HTMLElement} [canvas] If specified, use this canvas rather than
  *   a canvas associaied with the renderer directly.  Renderers may not support
  *   sharing a canvas.
@@ -137,7 +140,7 @@ var layer = function (arg) {
   /**
    * Get the setting of autoshareRenderer.
    *
-   * @returns {boolean}
+   * @returns {boolean|string}
    */
   this.autoshareRenderer = function () {
     return m_autoshareRenderer;
diff --git a/src/map.js b/src/map.js
index 39fca1d5fb..f292668c9e 100644
--- a/src/map.js
+++ b/src/map.js
@@ -56,6 +56,9 @@ var sceneObject = require('./sceneObject');
  *   maximum bounds in the vertical direction.
  * @property {boolean} [clampZoom=true] Prevent zooming out so that the map
  *   area is smaller than the window.
+ * @property {boolean|string} [autoshareRenderer] If specified, pass this value
+ *   to layers when they are created.  See
+ *   {@link geo.layer.spec#autoshareRenderer} for valid values.
  */
 
 /**
@@ -133,6 +136,7 @@ var map = function (arg) {
       m_clampZoom,
       m_animationQueue = arg.animationQueue || [],
       m_autoResize = arg.autoResize === undefined ? true : arg.autoResize,
+      m_autoshareRenderer = arg.autoshareRenderer,
       m_origin;
 
   /* Compute the maximum bounds on our map projection.  By default, x ranges
@@ -614,6 +618,9 @@ var map = function (arg) {
    */
   this.createLayer = function (layerName, arg) {
     arg = arg || {};
+    if (m_this.autoshareRenderer() !== undefined) {
+      arg = Object.assign({autoshareRenderer: m_this.autoshareRenderer()}, arg);
+    }
     var newLayer = registry.createLayer(
       layerName, m_this, arg);
 
@@ -1873,6 +1880,22 @@ var map = function (arg) {
     return zoom;
   };
 
+  /**
+   * Get or set the setting of autoshareRenderer.
+   *
+   * @param {boolean|string|null} [arg] If specified, the new value for
+   *   autoshareRender that gets passed to created layers.  `null` will clear
+   *   the value.
+   * @returns {boolean|string|this}
+   */
+  this.autoshareRenderer = function (arg) {
+    if (arg === undefined) {
+      return m_autoshareRenderer;
+    }
+    m_autoshareRenderer = arg === null ? undefined : arg;
+    return m_this;
+  };
+
   /**
    * Draw a layer image to a canvas context.  The layer's opacity and transform
    * are applied.  This is used as part of making a screenshot.
diff --git a/src/webgl/layer.js b/src/webgl/layer.js
index 1de01d8644..f14146d839 100644
--- a/src/webgl/layer.js
+++ b/src/webgl/layer.js
@@ -6,6 +6,7 @@ var webgl_layer = function () {
   var createRenderer = require('../registry').createRenderer;
   var geo_event = require('../event');
   var webglRenderer = require('./webglRenderer');
+  var tileLayer = require('../tileLayer');
 
   var m_this = this,
       s_init = this._init,
@@ -137,23 +138,28 @@ var webgl_layer = function () {
         var layers = map.sortedLayers(),
             renderer,
             rerender_list = [],
-            opacity;
+            opacity,
+            lowerTileLayers;
         layers.forEach(function (layer) {
-          if (!layer.autoshareRenderer() || !layer.renderer() || layer.renderer().api() !== webglRenderer.apiname) {
+          let autoshare = layer.autoshareRenderer(),
+              isTileLayer = layer instanceof tileLayer;
+          if (!autoshare || !layer.renderer() || layer.renderer().api() !== webglRenderer.apiname) {
             renderer = null;
-          } else if (!renderer || layer.opacity() !== opacity) {
+          } else if (!renderer || layer.opacity() !== opacity || (autoshare !== 'more' && ((layer.opacity() > 0 && layer.opacity() < 1) || (isTileLayer && !lowerTileLayers)))) {
             if (!layer.node()[0].contains(layer.renderer().canvas()[0])) {
               layer.switchRenderer(createRenderer(webglRenderer.apiname, layer), false);
               rerender_list.push(layer.renderer());
             }
             renderer = layer.renderer();
             opacity = layer.opacity();
+            lowerTileLayers = isTileLayer;
           } else {
             if (layer.renderer() !== renderer) {
               rerender_list.push(layer.renderer());
               layer.switchRenderer(renderer, false);
               rerender_list.push(layer.renderer());
             }
+            lowerTileLayers &= isTileLayer;
           }
         });
         layers.forEach(function (layer) {
diff --git a/src/webgl/tileLayer.js b/src/webgl/tileLayer.js
index 4c4244a67f..f91fdd90b3 100644
--- a/src/webgl/tileLayer.js
+++ b/src/webgl/tileLayer.js
@@ -3,6 +3,9 @@ var tileLayer = require('../tileLayer');
 
 var webgl_tileLayer = function () {
   'use strict';
+
+  var geo_event = require('../event');
+
   var m_this = this,
       s_init = this._init,
       s_exit = this._exit,
@@ -132,16 +135,28 @@ var webgl_tileLayer = function () {
    */
   this.zIndex = function (zIndex, allowDuplicate) {
     if (zIndex !== undefined) {
-      /* If the z-index has changed, clear the quads so they are composited in
-       * the correct order. */
-      m_this.clear();
-      if (m_quadFeature) {
-        m_quadFeature.modified();
-      }
+      this._clearQuads(true);
     }
     return s_zIndex.apply(m_this, arguments);
   };
 
+  /**
+   * If the z-index has changed or layers are added or removed, clear the quads
+   * so they are composited in the correct order.
+   *
+   * @param {boolean} [noredraw] If truthy, don't redraw after clearing the
+   *    quads.
+   */
+  this._clearQuads = function (noredraw) {
+    m_this.clear();
+    if (m_quadFeature) {
+      m_quadFeature.modified();
+    }
+    if (noredraw !== true) {
+      this.draw();
+    }
+  };
+
   /**
    * Update layer.
    *
@@ -197,6 +212,10 @@ var webgl_tileLayer = function () {
     m_quadFeature.gcs(m_this._options.gcs || m_this.map().gcs());
     m_quadFeature.data(m_tiles);
     m_quadFeature._update();
+
+    var map = m_this.map();
+    map.geoOn(geo_event.layerAdd, this._clearQuads);
+    map.geoOn(geo_event.layerRemove, this._clearQuads);
   };
 
   /* These functions don't need to do anything. */
diff --git a/tests/cases/layer.js b/tests/cases/layer.js
index ba1ba88402..e74d9e9b08 100644
--- a/tests/cases/layer.js
+++ b/tests/cases/layer.js
@@ -323,7 +323,7 @@ describe('geo.webgl.layer', function () {
       restoreWebglRenderer();
     });
   });
-  describe('autoshareRenderer is true', function () {
+  describe('autoshareRenderer is true"', function () {
     var map, layer1, layer2, layer3;
     it('_init', function (done) {
       mockWebglRenderer();
@@ -348,6 +348,68 @@ describe('geo.webgl.layer', function () {
       layer2.visible(true);
       expect($('canvas', map.node()).length).toBe(1);
     });
+    it('opacity', function () {
+      layer1.opacity(0.5);
+      expect($('canvas', map.node()).length).toBe(2);
+      layer2.opacity(0.5);
+      expect($('canvas', map.node()).length).toBe(3);
+      layer1.opacity(1);
+      expect($('canvas', map.node()).length).toBe(3);
+      layer2.opacity(1);
+      expect($('canvas', map.node()).length).toBe(1);
+    });
+    it('zIndex', function () {
+      expect($('canvas', layer1.node()).length).toBe(1);
+      expect($('canvas', layer2.node()).length).toBe(0);
+      expect($('canvas', layer3.node()).length).toBe(0);
+      layer1.moveUp();
+      expect($('canvas', map.node()).length).toBe(1);
+      expect($('canvas', layer1.node()).length).toBe(0);
+      expect($('canvas', layer2.node()).length).toBe(1);
+      expect($('canvas', layer3.node()).length).toBe(0);
+      layer1.moveUp();
+      expect($('canvas', map.node()).length).toBe(2);
+      expect($('canvas', layer1.node()).length).toBe(1);
+      expect($('canvas', layer2.node()).length).toBe(1);
+      expect($('canvas', layer3.node()).length).toBe(0);
+      layer1.moveToBottom();
+      expect($('canvas', map.node()).length).toBe(1);
+      expect($('canvas', layer1.node()).length).toBe(1);
+      expect($('canvas', layer2.node()).length).toBe(0);
+      expect($('canvas', layer3.node()).length).toBe(0);
+    });
+    it('cleanup', function () {
+      console.log.restore();
+      destroyMap();
+      restoreWebglRenderer();
+    });
+  });
+  describe('autoshareRenderer is "more"', function () {
+    var map, layer1, layer2, layer3;
+    it('_init', function (done) {
+      mockWebglRenderer();
+      sinon.stub(console, 'log', function () {});
+      map = createMap();
+      map.autoshareRenderer('more');
+      layer1 = map.createLayer('osm', {renderer: 'webgl', url: '/testdata/white.jpg'});
+      layer2 = map.createLayer('osm', {renderer: 'webgl', url: '/testdata/weather.png', keepLower: false});
+      layer3 = map.createLayer('feature', {renderer: 'webgl'});
+      layer3.createFeature('point', {}).data([{x: 2, y: 1}]);
+      map.onIdle(function () {
+        expect($('canvas', map.node()).length).toBe(1);
+        done();
+      });
+    });
+    it('visible', function () {
+      layer1.visible(false);
+      expect($('canvas', map.node()).length).toBe(1);
+      layer1.visible(true);
+      expect($('canvas', map.node()).length).toBe(1);
+      layer2.visible(false);
+      expect($('canvas', map.node()).length).toBe(1);
+      layer2.visible(true);
+      expect($('canvas', map.node()).length).toBe(1);
+    });
     it('opacity', function () {
       layer1.opacity(0.5);
       expect($('canvas', map.node()).length).toBe(2);
@@ -390,9 +452,9 @@ describe('geo.webgl.layer', function () {
       mockWebglRenderer();
       sinon.stub(console, 'log', function () {});
       map = createMap();
-      layer1 = map.createLayer('osm', {renderer: 'webgl', url: '/testdata/white.jpg'});
+      layer1 = map.createLayer('osm', {renderer: 'webgl', url: '/testdata/white.jpg', autoshareRenderer: 'more'});
       layer2 = map.createLayer('osm', {renderer: 'webgl', url: '/testdata/weather.png', keepLower: false, autoshareRenderer: false});
-      layer3 = map.createLayer('feature', {renderer: 'webgl'});
+      layer3 = map.createLayer('feature', {renderer: 'webgl', autoshareRenderer: 'more'});
       layer3.createFeature('point', {}).data([{x: 2, y: 1}]);
       map.onIdle(function () {
         expect($('canvas', map.node()).length).toBe(3);
diff --git a/tests/cases/map.js b/tests/cases/map.js
index e610663398..314abba943 100644
--- a/tests/cases/map.js
+++ b/tests/cases/map.js
@@ -408,6 +408,18 @@ describe('geo.core.map', function () {
       expect(m.fileReader(r)).toBe(m);
       expect(m.fileReader()).toBe(r);
     });
+    it('autoshareRenderer', function () {
+      var m = createMap();
+      expect(m.autoshareRenderer()).toBe(undefined);
+      expect(m.autoshareRenderer(false)).toBe(m);
+      expect(m.autoshareRenderer()).toBe(false);
+      expect(m.autoshareRenderer(true)).toBe(m);
+      expect(m.autoshareRenderer()).toBe(true);
+      expect(m.autoshareRenderer(null)).toBe(m);
+      expect(m.autoshareRenderer()).toBe(undefined);
+      m = createMap({autoshareRenderer: 'more'});
+      expect(m.autoshareRenderer()).toBe('more');
+    });
   });
 
   describe('Public utility methods', function () {