diff --git a/src/ol/control/mousepositioncontrol.js b/src/ol/control/mousepositioncontrol.js
index 09abf92d4b..0f3cfb9400 100644
--- a/src/ol/control/mousepositioncontrol.js
+++ b/src/ol/control/mousepositioncontrol.js
@@ -8,6 +8,7 @@ goog.require('goog.dom');
 goog.require('goog.events');
 goog.require('goog.events.EventType');
 goog.require('goog.style');
+goog.require('ol.Coordinate');
 goog.require('ol.CoordinateFormatType');
 goog.require('ol.MapEvent');
 goog.require('ol.MapEventType');
@@ -177,7 +178,8 @@ ol.control.MousePosition.prototype.updateHTML_ = function(pixel) {
     var map = this.getMap();
     var coordinate = map.getCoordinateFromPixel(pixel);
     if (!goog.isNull(coordinate)) {
-      coordinate = this.transform_(coordinate);
+      var output = this.transform_([coordinate.x, coordinate.y]);
+      coordinate = new ol.Coordinate(output[0], output[1]);
       if (goog.isDef(this.coordinateFormat_)) {
         html = this.coordinateFormat_(coordinate);
       } else {
diff --git a/src/ol/extent.js b/src/ol/extent.js
index 3606dfc63c..0edfa2a8ca 100644
--- a/src/ol/extent.js
+++ b/src/ol/extent.js
@@ -108,8 +108,10 @@ ol.Extent.prototype.getTopRight = function() {
  * @return {ol.Extent} Extent.
  */
 ol.Extent.prototype.transform = function(transformFn) {
-  var a = transformFn(new ol.Coordinate(this.minX, this.minY));
-  var b = transformFn(new ol.Coordinate(this.maxX, this.maxY));
-  return new ol.Extent(Math.min(a.x, b.x), Math.min(a.y, b.y),
-      Math.max(a.x, b.x), Math.max(a.y, b.y));
+  var input = [this.minX, this.minY, this.maxX, this.maxY];
+  var output = transformFn(input, 2);
+  return new ol.Extent(Math.min(output[0], output[2]),
+      Math.min(output[1], output[3]),
+      Math.max(output[0], output[2]),
+      Math.max(output[1], output[3]));
 };
diff --git a/src/ol/geolocation.js b/src/ol/geolocation.js
index 201257e2eb..69052832b2 100644
--- a/src/ol/geolocation.js
+++ b/src/ol/geolocation.js
@@ -76,11 +76,12 @@ ol.Geolocation.prototype.disposeInternal = function() {
 ol.Geolocation.prototype.handleProjectionChanged_ = function() {
   var projection = this.getProjection();
   if (goog.isDefAndNotNull(projection)) {
-    this.transformCoords_ = ol.projection.getTransform(
+    this.transformFn_ = ol.projection.getTransform(
         ol.projection.getFromCode('EPSG:4326'), projection);
     if (!goog.isNull(this.position_)) {
+      var output = this.transformFn_([this.position_.x, this.position_.y]);
       this.set(ol.GeolocationProperty.POSITION,
-          this.transformCoords_(this.position_));
+          new ol.Coordinate(output[0], output[1]));
     }
   }
 };
@@ -108,8 +109,9 @@ ol.Geolocation.prototype.positionChange_ = function(position) {
   this.set(ol.GeolocationProperty.HEADING, goog.isNull(coords.heading) ?
       undefined : goog.math.toRadians(coords.heading));
   this.position_ = new ol.Coordinate(coords.longitude, coords.latitude);
+  var output = this.transformFn_([coords.longitude, coords.latitude]);
   this.set(ol.GeolocationProperty.POSITION,
-      this.transformCoords_(this.position_));
+      new ol.Coordinate(output[0], output[1]));
   this.set(ol.GeolocationProperty.SPEED,
       goog.isNull(coords.speed) ? undefined : coords.speed);
 };
@@ -230,7 +232,8 @@ goog.exportProperty(
 
 /**
  * @private
- * @param {ol.Coordinate} coordinate Coordinate.
- * @return {ol.Coordinate} Coordinate.
+ * @param {Array.<number>} input Input coordinate values.
+ * @param {number=} opt_dimension Dimension (default is 2).
+ * @return {Array.<number>} Output coordinate values.
  */
-ol.Geolocation.prototype.transformCoords_ = goog.functions.identity;
+ol.Geolocation.prototype.transformFn_ = goog.functions.identity;
diff --git a/src/ol/projection.js b/src/ol/projection.js
index 6c1e321f14..80e8c1dbe2 100644
--- a/src/ol/projection.js
+++ b/src/ol/projection.js
@@ -397,14 +397,29 @@ ol.projection.getTransform = function(source, destination) {
     var destinationProj4jsProj = proj4jsDestination.getProj4jsProj();
     transform =
         /**
-         * @param {ol.Coordinate} coordinate Coordinate.
-         * @return {ol.Coordinate} Coordinate.
+         * @param {Array.<number>} input Input coordinate values.
+         * @param {number=} opt_dimension Dimension.
+         * @return {Array.<number>} Output coordinate values.
          */
-        function(coordinate) {
-      var proj4jsPoint = new Proj4js.Point(coordinate.x, coordinate.y);
-      proj4jsPoint = Proj4js.transform(
-          sourceProj4jsProj, destinationProj4jsProj, proj4jsPoint);
-      return new ol.Coordinate(proj4jsPoint.x, proj4jsPoint.y);
+        function(input, opt_dimension) {
+      var length = input.length,
+          dimension = goog.isDef(opt_dimension) ? opt_dimension : 2,
+          output, proj4jsPoint;
+      if (dimension > 2) {
+        // preserve values beyond second dimension
+        output = input.slice();
+      } else {
+        output = new Array(length);
+      }
+      goog.asserts.assert(output.length % dimension === 0);
+      for (var i = 0; i < length; i += dimension) {
+        proj4jsPoint = new Proj4js.Point(input[i], input[i + 1]);
+        proj4jsPoint = Proj4js.transform(
+            sourceProj4jsProj, destinationProj4jsProj, proj4jsPoint);
+        output[i] = proj4jsPoint.x;
+        output[i + 1] = proj4jsPoint.y;
+      }
+      return output;
     };
     ol.projection.addTransform(source, destination, transform);
   }
@@ -418,7 +433,7 @@ ol.projection.getTransform = function(source, destination) {
 
 /**
  * Given the projection codes this method searches for a transformation function
- * to convert coordinate from the source projection to the destination
+ * to convert a coordinates array from the source projection to the destination
  * projection.
  *
  * @param {string} sourceCode Source code.
@@ -433,20 +448,23 @@ ol.projection.getTransformFromCodes = function(sourceCode, destinationCode) {
 
 
 /**
- * @param {ol.Coordinate} point Point.
- * @return {ol.Coordinate} Unaltered point (same reference).
+ * @param {Array.<number>} input Input coordinate array.
+ * @param {number=} opt_dimension Dimension.
+ * @return {Array.<number>} Input coordinate array (same array as input).
  */
-ol.projection.identityTransform = function(point) {
-  return point;
+ol.projection.identityTransform = function(input, opt_dimension) {
+  return input;
 };
 
 
 /**
- * @param {ol.Coordinate} point Point.
- * @return {ol.Coordinate} Equal point (different reference).
+ * @param {Array.<number>} input Input coordinate array.
+ * @param {number=} opt_dimension Dimension.
+ * @return {Array.<number>} Output coordinate array (new array, same coordinate
+ *     values).
  */
-ol.projection.cloneTransform = function(point) {
-  return new ol.Coordinate(point.x, point.y);
+ol.projection.cloneTransform = function(input, opt_dimension) {
+  return input.slice();
 };
 
 
@@ -460,7 +478,8 @@ ol.projection.cloneTransform = function(point) {
  */
 ol.projection.transform = function(point, source, destination) {
   var transformFn = ol.projection.getTransform(source, destination);
-  return transformFn(point);
+  var output = transformFn([point.x, point.y]);
+  return new ol.Coordinate(output[0], output[1]);
 };
 
 
@@ -474,5 +493,6 @@ ol.projection.transformWithCodes =
     function(point, sourceCode, destinationCode) {
   var transformFn = ol.projection.getTransformFromCodes(
       sourceCode, destinationCode);
-  return transformFn(point);
+  var output = transformFn([point.x, point.y]);
+  return new ol.Coordinate(output[0], output[1]);
 };
diff --git a/src/ol/projection/epsg3857.js b/src/ol/projection/epsg3857.js
index 991eca5410..2050aca7d2 100644
--- a/src/ol/projection/epsg3857.js
+++ b/src/ol/projection/epsg3857.js
@@ -1,7 +1,6 @@
 goog.provide('ol.projection.EPSG3857');
 
 goog.require('goog.array');
-goog.require('ol.Coordinate');
 goog.require('ol.Extent');
 goog.require('ol.Projection');
 goog.require('ol.ProjectionUnits');
@@ -73,26 +72,52 @@ ol.projection.EPSG3857.PROJECTIONS = goog.array.map(
 /**
  * Transformation from EPSG:4326 to EPSG:3857.
  *
- * @param {ol.Coordinate} point Point.
- * @return {ol.Coordinate} Point.
+ * @param {Array.<number>} input Input array of coordinate values.
+ * @param {number=} opt_dimension Dimension (default is 2).
+ * @return {Array.<number>} Output array of coordinate values.
  */
-ol.projection.EPSG3857.fromEPSG4326 = function(point) {
-  var x = ol.projection.EPSG3857.RADIUS * Math.PI * point.x / 180;
-  var y = ol.projection.EPSG3857.RADIUS *
-      Math.log(Math.tan(Math.PI * (point.y + 90) / 360));
-  return new ol.Coordinate(x, y);
+ol.projection.EPSG3857.fromEPSG4326 = function(input, opt_dimension) {
+  var length = input.length,
+      dimension = goog.isDef(opt_dimension) ? opt_dimension : 2,
+      output;
+  if (dimension > 2) {
+    // preserve values beyond second dimension
+    output = input.slice();
+  } else {
+    output = new Array(length);
+  }
+  goog.asserts.assert(output.length % dimension === 0);
+  for (var i = 0; i < length; i += dimension) {
+    output[i] = ol.projection.EPSG3857.RADIUS * Math.PI * input[i] / 180;
+    output[i + 1] = ol.projection.EPSG3857.RADIUS *
+        Math.log(Math.tan(Math.PI * (input[i + 1] + 90) / 360));
+  }
+  return output;
 };
 
 
 /**
  * Transformation from EPSG:3857 to EPSG:4326.
  *
- * @param {ol.Coordinate} point Point.
- * @return {ol.Coordinate} Point.
+ * @param {Array.<number>} input Input array of coordinate values.
+ * @param {number=} opt_dimension Dimension (default is 2).
+ * @return {Array.<number>} Output array of coordinate values.
  */
-ol.projection.EPSG3857.toEPSG4326 = function(point) {
-  var x = 180 * point.x / (ol.projection.EPSG3857.RADIUS * Math.PI);
-  var y = 360 * Math.atan(
-      Math.exp(point.y / ol.projection.EPSG3857.RADIUS)) / Math.PI - 90;
-  return new ol.Coordinate(x, y);
+ol.projection.EPSG3857.toEPSG4326 = function(input, opt_dimension) {
+  var length = input.length,
+      dimension = goog.isDef(opt_dimension) ? opt_dimension : 2,
+      output;
+  if (dimension > 2) {
+    // preserve values beyond second dimension
+    output = input.slice();
+  } else {
+    output = new Array(length);
+  }
+  goog.asserts.assert(output.length % dimension === 0);
+  for (var i = 0; i < length; i += dimension) {
+    output[i] = 180 * input[i] / (ol.projection.EPSG3857.RADIUS * Math.PI);
+    output[i + 1] = 360 * Math.atan(
+        Math.exp(input[i + 1] / ol.projection.EPSG3857.RADIUS)) / Math.PI - 90;
+  }
+  return output;
 };
diff --git a/src/ol/transformfunction.js b/src/ol/transformfunction.js
index a8be2c0f28..65b5a6c585 100644
--- a/src/ol/transformfunction.js
+++ b/src/ol/transformfunction.js
@@ -1,9 +1,11 @@
 goog.provide('ol.TransformFunction');
 
-goog.require('ol.Coordinate');
-
 
 /**
- * @typedef {function(ol.Coordinate): ol.Coordinate}
+ * A transform function accepts an array of input coordinate values and an
+ * optional dimension (default should be 2).  The function transforms the
+ * coordinate values and returns an array of the same length as the input.
+ *
+ * @typedef {function(Array.<number>, number=): Array.<number>}
  */
 ol.TransformFunction;
diff --git a/test/spec/ol/extent.test.js b/test/spec/ol/extent.test.js
index 11431db798..9cd1ba3c40 100644
--- a/test/spec/ol/extent.test.js
+++ b/test/spec/ol/extent.test.js
@@ -84,8 +84,8 @@ describe('ol.Extent', function() {
     });
 
     it('takes arbitrary function', function() {
-      var transformFn = function(coordinate) {
-        return new ol.Coordinate(-coordinate.x, -coordinate.y);
+      var transformFn = function(input) {
+        return [-input[0], -input[1], -input[2], -input[3]];
       };
       var sourceExtent = new ol.Extent(-15, -30, 45, 60);
       var destinationExtent = sourceExtent.transform(transformFn);
diff --git a/test/spec/ol/projection.test.js b/test/spec/ol/projection.test.js
index 42b3f09fc2..a840a6f0f4 100644
--- a/test/spec/ol/projection.test.js
+++ b/test/spec/ol/projection.test.js
@@ -155,10 +155,22 @@ describe('ol.projection', function() {
       var transform = ol.projection.getTransform(sm, gg);
       expect(typeof transform).toBe('function');
 
-      var coordinate = transform(new ol.Coordinate(-12000000, 5000000));
+      var output = transform([-12000000, 5000000]);
 
-      expect(coordinate.x).toRoughlyEqual(-107.79783409434258, 1e-9);
-      expect(coordinate.y).toRoughlyEqual(40.91627447067577, 1e-9);
+      expect(output[0]).toRoughlyEqual(-107.79783409434258, 1e-9);
+      expect(output[1]).toRoughlyEqual(40.91627447067577, 1e-9);
+    });
+
+    it('works for longer arrays', function() {
+      var transform = ol.projection.getTransform(sm, gg);
+      expect(typeof transform).toBe('function');
+
+      var output = transform([-12000000, 5000000, -12000000, 5000000]);
+
+      expect(output[0]).toRoughlyEqual(-107.79783409434258, 1e-9);
+      expect(output[1]).toRoughlyEqual(40.91627447067577, 1e-9);
+      expect(output[2]).toRoughlyEqual(-107.79783409434258, 1e-9);
+      expect(output[3]).toRoughlyEqual(40.91627447067577, 1e-9);
     });
 
   });
@@ -177,14 +189,54 @@ describe('ol.projection', function() {
           'GOOGLE', 'EPSG:4326');
       expect(typeof transform).toBe('function');
 
-      var coordinate = transform(
-          new ol.Coordinate(-626172.13571216376, 6887893.4928337997));
+      var output = transform([-626172.13571216376, 6887893.4928337997]);
 
-      expect(coordinate.x).toRoughlyEqual(-5.625, 1e-9);
-      expect(coordinate.y).toRoughlyEqual(52.4827802220782, 1e-9);
+      expect(output[0]).toRoughlyEqual(-5.625, 1e-9);
+      expect(output[1]).toRoughlyEqual(52.4827802220782, 1e-9);
 
     });
 
+    it('works for longer arrays of coordinate values', function() {
+      var transform = ol.projection.getTransformFromCodes(
+          'GOOGLE', 'EPSG:4326');
+      expect(typeof transform).toBe('function');
+
+      var output = transform([
+        -626172.13571216376, 6887893.4928337997,
+        -12000000, 5000000,
+        -626172.13571216376, 6887893.4928337997
+      ]);
+
+      expect(output[0]).toRoughlyEqual(-5.625, 1e-9);
+      expect(output[1]).toRoughlyEqual(52.4827802220782, 1e-9);
+      expect(output[2]).toRoughlyEqual(-107.79783409434258, 1e-9);
+      expect(output[3]).toRoughlyEqual(40.91627447067577, 1e-9);
+      expect(output[4]).toRoughlyEqual(-5.625, 1e-9);
+      expect(output[5]).toRoughlyEqual(52.4827802220782, 1e-9);
+    });
+
+    it('accepts a dimension', function() {
+      var transform = ol.projection.getTransformFromCodes(
+          'GOOGLE', 'EPSG:4326');
+      expect(typeof transform).toBe('function');
+
+      var dimension = 3;
+      var output = transform([
+        -626172.13571216376, 6887893.4928337997, 100,
+        -12000000, 5000000, 200,
+        -626172.13571216376, 6887893.4928337997, 300
+      ], dimension);
+
+      expect(output[0]).toRoughlyEqual(-5.625, 1e-9);
+      expect(output[1]).toRoughlyEqual(52.4827802220782, 1e-9);
+      expect(output[2]).toBe(100);
+      expect(output[3]).toRoughlyEqual(-107.79783409434258, 1e-9);
+      expect(output[4]).toRoughlyEqual(40.91627447067577, 1e-9);
+      expect(output[5]).toBe(200);
+      expect(output[6]).toRoughlyEqual(-5.625, 1e-9);
+      expect(output[7]).toRoughlyEqual(52.4827802220782, 1e-9);
+      expect(output[8]).toBe(300);
+    });
   });
 
   describe('ol.projection.removeTransform()', function() {
@@ -195,7 +247,7 @@ describe('ol.projection', function() {
     it('removes functions cached by addTransform', function() {
       var foo = new ol.Projection('foo', units, extent);
       var bar = new ol.Projection('bar', units, extent);
-      var transform = function() {};
+      var transform = function(intput, dimension) {return input};
       ol.projection.addTransform(foo, bar, transform);
       expect(ol.projection.transforms_).not.toBeUndefined();
       expect(ol.projection.transforms_.foo).not.toBeUndefined();