diff --git a/modules/modes/select.js b/modules/modes/select.js
index 0b4c8e4e9..4289a0dc1 100644
--- a/modules/modes/select.js
+++ b/modules/modes/select.js
@@ -195,7 +195,7 @@ export function modeSelect(context, selectedIDs) {
     mode.zoomToSelected = function() {
         var entity = singular();
         if (entity) {
-            context.map().zoomTo(entity);
+            context.map().zoomToEase(entity);
         }
     };
 
diff --git a/modules/modes/select_data.js b/modules/modes/select_data.js
index 744800654..a32217175 100644
--- a/modules/modes/select_data.js
+++ b/modules/modes/select_data.js
@@ -64,7 +64,7 @@ export function modeSelectData(context, selectedDatum) {
 
     mode.zoomToSelected = function() {
         var extent = geoExtent(d3_geoBounds(selectedDatum));
-        context.map().centerZoom(extent.center(), context.map().trimmedExtentZoom(extent));
+        context.map().centerZoomEase(extent.center(), context.map().trimmedExtentZoom(extent));
     };
 
 
diff --git a/modules/modes/select_error.js b/modules/modes/select_error.js
index aa0c8ef3b..dbdae8aff 100644
--- a/modules/modes/select_error.js
+++ b/modules/modes/select_error.js
@@ -58,7 +58,7 @@ export function modeSelectError(context, selectedErrorID) {
         if (!keepRight) return;
         var error = keepRight.getError(selectedErrorID);
         if (error) {
-            context.map().centerZoom(error.loc, 20);
+            context.map().centerZoomEase(error.loc, 20);
         }
     };
 
diff --git a/modules/modes/select_note.js b/modules/modes/select_note.js
index 099d97a15..cd0187abb 100644
--- a/modules/modes/select_note.js
+++ b/modules/modes/select_note.js
@@ -90,7 +90,7 @@ export function modeSelectNote(context, selectedNoteID) {
         if (!osm) return;
         var note = osm.getNote(selectedNoteID);
         if (note) {
-            context.map().centerZoom(note.loc, 20);
+            context.map().centerZoomEase(note.loc, 20);
         }
     };
 
diff --git a/modules/renderer/map.js b/modules/renderer/map.js
index 7d23a7929..d8f3ef459 100644
--- a/modules/renderer/map.js
+++ b/modules/renderer/map.js
@@ -34,6 +34,10 @@ var TILESIZE = 256;
 var kMin = geoZoomToScale(2, TILESIZE);
 var kMax = geoZoomToScale(24, TILESIZE);
 
+function clamp(num, min, max) {
+    return Math.max(min, Math.min(num, max));
+}
+
 
 export function rendererMap(context) {
     var dispatch = d3_dispatch('move', 'drawn');
@@ -52,16 +56,16 @@ export function rendererMap(context) {
     var wrapper = d3_select(null);
     var surface = d3_select(null);
 
-    var dimensions = [1, 1];
+    var _dimensions = [1, 1];
     var _dblClickEnabled = true;
     var _redrawEnabled = true;
     var _gestureTransformStart;
     var _transformStart = projection.transform();
     var _transformLast;
-    var _transformed = false;
-    var minzoom = 0;
-    var mouse;
-    var mousemove;
+    var _isTransformed = false;
+    var _minzoom = 0;
+    var _getMouseCoords;
+    var _mouseEvent;
 
     var zoom = d3_zoom()
         .scaleExtent([kMin, kMax])
@@ -170,17 +174,17 @@ export function rendererMap(context) {
                 }
             })
             .on('mousemove.map', function() {
-                mousemove = d3_event;
+                _mouseEvent = d3_event;
             })
             .on('mouseover.vertices', function() {
-                if (map.editable() && !_transformed) {
+                if (map.editable() && !_isTransformed) {
                     var hover = d3_event.target.__data__;
                     surface.call(drawVertices.drawHover, context.graph(), hover, map.extent());
                     dispatch.call('drawn', this, { full: false });
                 }
             })
             .on('mouseout.vertices', function() {
-                if (map.editable() && !_transformed) {
+                if (map.editable() && !_isTransformed) {
                     var hover = d3_event.relatedTarget && d3_event.relatedTarget.__data__;
                     surface.call(drawVertices.drawHover, context.graph(), hover, map.extent());
                     dispatch.call('drawn', this, { full: false });
@@ -191,7 +195,7 @@ export function rendererMap(context) {
             .call(context.background());
 
         context.on('enter.map',  function() {
-            if (map.editable() && !_transformed) {
+            if (map.editable() && !_isTransformed) {
                 // redraw immediately any objects affected by a change in selectedIDs.
                 var graph = context.graph();
                 var selectedAndParents = {};
@@ -263,7 +267,7 @@ export function rendererMap(context) {
 
 
     function pxCenter() {
-        return [dimensions[0] / 2, dimensions[1] / 2];
+        return [_dimensions[0] / 2, _dimensions[1] / 2];
     }
 
 
@@ -285,7 +289,7 @@ export function rendererMap(context) {
         } else {
             // force a full redraw if gatherStats detects that a feature
             // should be auto-hidden (e.g. points or buildings)..
-            if (features.gatherStats(all, graph, dimensions)) {
+            if (features.gatherStats(all, graph, _dimensions)) {
                 extent = undefined;
             }
 
@@ -314,7 +318,7 @@ export function rendererMap(context) {
             .call(drawLines, graph, data, filter)
             .call(drawAreas, graph, data, filter)
             .call(drawMidpoints, graph, data, filter, map.trimmedExtent())
-            .call(drawLabels, graph, data, filter, dimensions, fullRedraw)
+            .call(drawLabels, graph, data, filter, _dimensions, fullRedraw)
             .call(drawPoints, graph, data, filter);
 
         dispatch.call('drawn', this, {full: true});
@@ -422,8 +426,8 @@ export function rendererMap(context) {
                 }
 
                 // recalculate x2,y2,k2
-                t0 = _transformed ? _transformLast : _transformStart;
-                p0 = mouse(source);
+                t0 = _isTransformed ? _transformLast : _transformStart;
+                p0 = _getMouseCoords(source);
                 p1 = t0.invert(p0);
                 k2 = t0.k * Math.pow(2, -dY / 500);
                 x2 = p0[0] - p1[0] * k2;
@@ -434,7 +438,7 @@ export function rendererMap(context) {
             } else if (source._scale) {
                 // recalculate x2,y2,k2
                 t0 = _gestureTransformStart;
-                p0 = mouse(source);
+                p0 = _getMouseCoords(source);
                 p1 = t0.invert(p0);
                 k2 = t0.k * source._scale;
                 x2 = p0[0] - p1[0] * k2;
@@ -448,8 +452,8 @@ export function rendererMap(context) {
                 dY *= 6;   // slightly scale up whatever the browser gave us
 
                 // recalculate x2,y2,k2
-                t0 = _transformed ? _transformLast : _transformStart;
-                p0 = mouse(source);
+                t0 = _isTransformed ? _transformLast : _transformStart;
+                p0 = _getMouseCoords(source);
                 p1 = t0.invert(p0);
                 k2 = t0.k * Math.pow(2, -dY / 500);
                 x2 = p0[0] - p1[0] * k2;
@@ -458,8 +462,8 @@ export function rendererMap(context) {
             // Trackpad scroll zooming with shift or alt/option key down
             } else if ((source.altKey || source.shiftKey) && isInteger(dY)) {
                 // recalculate x2,y2,k2
-                t0 = _transformed ? _transformLast : _transformStart;
-                p0 = mouse(source);
+                t0 = _isTransformed ? _transformLast : _transformStart;
+                p0 = _getMouseCoords(source);
                 p1 = t0.invert(p0);
                 k2 = t0.k * Math.pow(2, -dY / 500);
                 x2 = p0[0] - p1[0] * k2;
@@ -487,7 +491,7 @@ export function rendererMap(context) {
 
         }
 
-        if (geoScaleToZoom(k, TILESIZE) < minzoom) {
+        if (geoScaleToZoom(k, TILESIZE) < _minzoom) {
             surface.interrupt();
             uiFlash().text(t('cannot_zoom'))();
             setCenterZoom(map.center(), context.minEditableZoom(), 0, true);
@@ -510,8 +514,10 @@ export function rendererMap(context) {
             });
         }
 
-        if (source) mousemove = event;
-        _transformed = true;
+        if (source) {
+            _mouseEvent = event;
+        }
+        _isTransformed = true;
         _transformLast = eventTransform;
         utilSetTransform(supersurface, tX, tY, scale);
         scheduleRedraw();
@@ -519,10 +525,6 @@ export function rendererMap(context) {
         dispatch.call('move', this, map);
 
 
-        function clamp(num, min, max) {
-            return Math.max(min, Math.min(num, max));
-        }
-
         function isInteger(val) {
             return typeof val === 'number' && isFinite(val) && Math.floor(val) === val;
         }
@@ -530,12 +532,12 @@ export function rendererMap(context) {
 
 
     function resetTransform() {
-        if (!_transformed) return false;
+        if (!_isTransformed) return false;
 
         // deprecation warning - Radial Menu to be removed in iD v3
         surface.selectAll('.edit-menu, .radial-menu').interrupt().remove();
         utilSetTransform(supersurface, 0, 0);
-        _transformed = false;
+        _isTransformed = false;
         if (context.inIntro()) {
             curtainProjection.transform(projection.transform());
         }
@@ -600,11 +602,11 @@ export function rendererMap(context) {
 
 
     map.mouse = function() {
-        var event = mousemove || d3_event;
+        var event = _mouseEvent || d3_event;
         if (event) {
             var s;
             while ((s = event.sourceEvent)) { event = s; }
-            return mouse(event);
+            return _getMouseCoords(event);
         }
         return null;
     };
@@ -617,22 +619,22 @@ export function rendererMap(context) {
     };
 
 
-    map.dblclickEnable = function(_) {
+    map.dblclickEnable = function(val) {
         if (!arguments.length) return _dblClickEnabled;
-        _dblClickEnabled = _;
+        _dblClickEnabled = val;
         return map;
     };
 
 
-    map.redrawEnable = function(_) {
+    map.redrawEnable = function(val) {
         if (!arguments.length) return _redrawEnabled;
-        _redrawEnabled = _;
+        _redrawEnabled = val;
         return map;
     };
 
 
     map.isTransformed = function() {
-        return _transformed;
+        return _isTransformed;
     };
 
 
@@ -663,7 +665,7 @@ export function rendererMap(context) {
 
         var proj = geoRawMercator().transform(projection.transform());  // copy projection
 
-        var k2 = Math.max(kMin, Math.min(kMax, geoZoomToScale(z2, TILESIZE)));
+        var k2 = clamp(geoZoomToScale(z2, TILESIZE), kMin, kMax);
         proj.scale(k2);
 
         var t = proj.translate();
@@ -702,13 +704,14 @@ export function rendererMap(context) {
     };
 
 
-    map.dimensions = function(_) {
-        if (!arguments.length) return dimensions;
-        dimensions = _;
-        drawLayers.dimensions(dimensions);
-        context.background().dimensions(dimensions);
-        projection.clipExtent([[0, 0], dimensions]);
-        mouse = utilFastMouse(supersurface.node());
+    map.dimensions = function(val) {
+        if (!arguments.length) return _dimensions;
+
+        _dimensions = val;
+        drawLayers.dimensions(_dimensions);
+        context.background().dimensions(_dimensions);
+        projection.clipExtent([[0, 0], _dimensions]);
+        _getMouseCoords = utilFastMouse(supersurface.node());
 
         scheduleRedraw();
         return map;
@@ -749,7 +752,7 @@ export function rendererMap(context) {
             return Math.max(geoScaleToZoom(projection.scale(), TILESIZE), 0);
         }
 
-        if (z2 < minzoom) {
+        if (z2 < _minzoom) {
             surface.interrupt();
             uiFlash().text(t('cannot_zoom'))();
             z2 = context.minEditableZoom();
@@ -764,16 +767,6 @@ export function rendererMap(context) {
     };
 
 
-    map.zoomTo = function(entity, zoomLimits) {
-        var extent = entity.extent(context.graph());
-        if (!isFinite(extent.area())) return;
-
-        var z2 = map.trimmedExtentZoom(extent);
-        zoomLimits = zoomLimits || [context.minEditableZoom(), 20];
-        map.centerZoom(extent.center(), Math.min(Math.max(z2, zoomLimits[0]), zoomLimits[1]));
-    };
-
-
     map.centerZoom = function(loc2, z2) {
         if (setCenterZoom(loc2, z2)) {
             dispatch.call('move', this, map);
@@ -784,6 +777,15 @@ export function rendererMap(context) {
     };
 
 
+    map.zoomTo = function(entity) {
+        var extent = entity.extent(context.graph());
+        if (!isFinite(extent.area())) return map;
+
+        var z2 = clamp(map.trimmedExtentZoom(extent), context.minEditableZoom(), 20);
+        return map.centerZoom(extent.center(), z2);
+    };
+
+
     map.centerEase = function(loc2, duration) {
         duration = duration || 250;
         setCenterZoom(loc2, map.zoom(), duration);
@@ -812,6 +814,15 @@ export function rendererMap(context) {
     };
 
 
+    map.zoomToEase = function(entity, duration) {
+        var extent = entity.extent(context.graph());
+        if (!isFinite(extent.area())) return map;
+
+        var z2 = clamp(map.trimmedExtentZoom(extent), context.minEditableZoom(), 20);
+        return map.centerZoomEase(extent.center(), z2, duration);
+    };
+
+
     map.startEase = function() {
         utilBindOnce(surface, 'mousedown.ease', function() {
             map.cancelEase();
@@ -826,36 +837,36 @@ export function rendererMap(context) {
     };
 
 
-    map.extent = function(_) {
+    map.extent = function(val) {
         if (!arguments.length) {
             return new geoExtent(
-                projection.invert([0, dimensions[1]]),
-                projection.invert([dimensions[0], 0])
+                projection.invert([0, _dimensions[1]]),
+                projection.invert([_dimensions[0], 0])
             );
         } else {
-            var extent = geoExtent(_);
+            var extent = geoExtent(val);
             map.centerZoom(extent.center(), map.extentZoom(extent));
         }
     };
 
 
-    map.trimmedExtent = function(_) {
+    map.trimmedExtent = function(val) {
         if (!arguments.length) {
             var headerY = 60;
             var footerY = 30;
             var pad = 10;
             return new geoExtent(
-                projection.invert([pad, dimensions[1] - footerY - pad]),
-                projection.invert([dimensions[0] - pad, headerY + pad])
+                projection.invert([pad, _dimensions[1] - footerY - pad]),
+                projection.invert([_dimensions[0] - pad, headerY + pad])
             );
         } else {
-            var extent = geoExtent(_);
+            var extent = geoExtent(val);
             map.centerZoom(extent.center(), map.trimmedExtentZoom(extent));
         }
     };
 
 
-    function calcZoom(extent, dim) {
+    function calcExtentZoom(extent, dim) {
         var tl = projection([extent[0][0], extent[1][1]]);
         var br = projection([extent[1][0], extent[0][1]]);
 
@@ -870,16 +881,16 @@ export function rendererMap(context) {
     }
 
 
-    map.extentZoom = function(_) {
-        return calcZoom(geoExtent(_), dimensions);
+    map.extentZoom = function(val) {
+        return calcExtentZoom(geoExtent(val), _dimensions);
     };
 
 
-    map.trimmedExtentZoom = function(_) {
+    map.trimmedExtentZoom = function(val) {
         var trimY = 120;
         var trimX = 40;
-        var trimmed = [dimensions[0] - trimX, dimensions[1] - trimY];
-        return calcZoom(geoExtent(_), trimmed);
+        var trimmed = [_dimensions[0] - trimX, _dimensions[1] - trimY];
+        return calcExtentZoom(geoExtent(val), trimmed);
     };
 
 
@@ -899,9 +910,9 @@ export function rendererMap(context) {
     };
 
 
-    map.minzoom = function(_) {
-        if (!arguments.length) return minzoom;
-        minzoom = _;
+    map.minzoom = function(val) {
+        if (!arguments.length) return _minzoom;
+        _minzoom = val;
         return map;
     };
 
diff --git a/modules/ui/commit_changes.js b/modules/ui/commit_changes.js
index 7ae906963..54cfd5898 100644
--- a/modules/ui/commit_changes.js
+++ b/modules/ui/commit_changes.js
@@ -150,7 +150,7 @@ export function uiCommitChanges(context) {
             } else {
                 var entity = change.entity;
                 _entityID = change.entity.id;
-                context.map().zoomTo(entity);
+                context.map().zoomToEase(entity);
                 context.surface().selectAll(utilEntityOrMemberSelector([_entityID], context.graph()))
                     .classed('hover', true);
             }
diff --git a/modules/ui/conflicts.js b/modules/ui/conflicts.js
index 9bb0e1252..6fee72c21 100644
--- a/modules/ui/conflicts.js
+++ b/modules/ui/conflicts.js
@@ -310,7 +310,7 @@ export function uiConflicts(context) {
             if (extent) {
                 context.map().trimmedExtent(extent);
             } else {
-                context.map().zoomTo(entity);
+                context.map().zoomToEase(entity);
             }
             context.surface().selectAll(utilEntityOrMemberSelector([entity.id], context.graph()))
                 .classed('hover', true);
diff --git a/modules/ui/feature_list.js b/modules/ui/feature_list.js
index 5bef2e1ba..0aefcf253 100644
--- a/modules/ui/feature_list.js
+++ b/modules/ui/feature_list.js
@@ -316,7 +316,7 @@ export function uiFeatureList(context) {
         function click(d) {
             d3_event.preventDefault();
             if (d.location) {
-                context.map().centerZoom([d.location[1], d.location[0]], 19);
+                context.map().centerZoomEase([d.location[1], d.location[0]], 19);
             }
             else if (d.entity) {
                 if (d.entity.type === 'node') {
diff --git a/modules/ui/geolocate.js b/modules/ui/geolocate.js
index 651196d05..465fa92e3 100644
--- a/modules/ui/geolocate.js
+++ b/modules/ui/geolocate.js
@@ -7,19 +7,19 @@ import { uiLoading } from './loading';
 
 
 export function uiGeolocate(context) {
-    var geoOptions = { enableHighAccuracy: false, timeout: 6000 /* 6sec */ },
-        locating = uiLoading(context).message(t('geolocate.locating')).blocking(true),
-        layer = context.layers().layer('geolocate'),
-        position,
-        extent,
-        timeoutId;
+    var geoOptions = { enableHighAccuracy: false, timeout: 6000 /* 6sec */ };
+    var locating = uiLoading(context).message(t('geolocate.locating')).blocking(true);
+    var layer = context.layers().layer('geolocate');
+    var _position;
+    var _extent;
+    var _timeoutID;
 
 
     function click() {
         if (context.inIntro()) return;
         context.enter(modeBrowse(context));
         if (!layer.enabled()) {
-            if (!position) {
+            if (!_position) {
                 context.container().call(locating);
                 navigator.geolocation.getCurrentPosition(success, error, geoOptions);
             } else {
@@ -30,21 +30,20 @@ export function uiGeolocate(context) {
         }
         // This timeout ensures that we still call finish() even if
         // the user declines to share their location in Firefox
-        timeoutId = setTimeout(finish, 10000 /* 10sec */ );
+        _timeoutID = setTimeout(finish, 10000 /* 10sec */ );
     }
 
     function zoomTo() {
         var map = context.map();
-        layer.enabled(position, true);
-        map.centerZoom(extent.center(), Math.min(20, map.extentZoom(extent)));
+        layer.enabled(_position, true);
+        map.centerZoomEase(_extent.center(), Math.min(20, map.extentZoom(_extent)));
     }
 
 
     function success(geolocation) {
-        position = geolocation;
-        extent = geoExtent([position.coords.longitude, position.coords.latitude])
-                    .padByMeters(position.coords.accuracy);
-
+        _position = geolocation;
+        var coords = _position.coords;
+        _extent = geoExtent([coords.longitude, coords.latitude]).padByMeters(coords.accuracy);
         zoomTo();
         finish();
     }
@@ -57,8 +56,8 @@ export function uiGeolocate(context) {
 
     function finish() {
         locating.close();  // unblock ui
-        if (timeoutId) { clearTimeout(timeoutId); }
-        timeoutId = undefined;
+        if (_timeoutID) { clearTimeout(_timeoutID); }
+        _timeoutID = undefined;
     }
 
 
diff --git a/modules/ui/keepRight_details.js b/modules/ui/keepRight_details.js
index ee164ac58..12d613448 100644
--- a/modules/ui/keepRight_details.js
+++ b/modules/ui/keepRight_details.js
@@ -92,7 +92,7 @@ export function uiKeepRightDetails(context) {
                             osmlayer.enabled(true);
                         }
 
-                        context.map().centerZoom(_error.loc, 20);
+                        context.map().centerZoomEase(_error.loc, 20);
 
                         if (entity) {
                             context.enter(modeSelect(context, [entityID]));
diff --git a/modules/ui/raw_member_editor.js b/modules/ui/raw_member_editor.js
index a6b52f60c..29ede036e 100644
--- a/modules/ui/raw_member_editor.js
+++ b/modules/ui/raw_member_editor.js
@@ -51,7 +51,7 @@ export function uiRawMemberEditor(context) {
         var mapExtent = context.map().extent();
         if (!entity.intersects(mapExtent, context.graph())) {
             // zoom to the entity if its extent is not visible now
-            context.map().zoomTo(entity);
+            context.map().zoomToEase(entity);
         }
 
         context.enter(modeSelect(context, [d.id]));