diff --git a/lib/OpenLayers/Control/PanZoom.js b/lib/OpenLayers/Control/PanZoom.js
index f335dc2e6d..e92036059b 100644
--- a/lib/OpenLayers/Control/PanZoom.js
+++ b/lib/OpenLayers/Control/PanZoom.js
@@ -21,10 +21,20 @@ OpenLayers.Control.PanZoom = OpenLayers.Class(OpenLayers.Control, {
     /** 
      * APIProperty: slideFactor
      * {Integer} Number of pixels by which we'll pan the map in any direction 
-     *     on clicking the arrow buttons. 
+     *     on clicking the arrow buttons.  If you want to pan by some ratio
+     *     of the map dimensions, use <slideRatio> instead.
      */
     slideFactor: 50,
 
+    /** 
+     * APIProperty: slideRatio
+     * {Number} The fraction of map width/height by which we'll pan the map            
+     *     on clicking the arrow buttons.  Default is null.  If set, will
+     *     override <slideFactor>. E.g. if slideRatio is .5, then the Pan Up
+     *     button will pan up half the map height. 
+     */
+    slideRatio: null,
+
     /** 
      * Property: buttons
      * {Array(DOMElement)} Array of Button Divs 
@@ -124,7 +134,20 @@ OpenLayers.Control.PanZoom = OpenLayers.Class(OpenLayers.Control, {
             OpenLayers.Function.bindAsEventListener(this.doubleClick, btn));
         btn.action = id;
         btn.map = this.map;
-        btn.slideFactor = this.slideFactor;
+    
+        if(!this.slideRatio){
+            var slideFactorPixels = this.slideFactor;
+            var getSlideFactor = function() {
+                return slideFactorPixels;
+            };
+        } else {
+            var slideRatio = this.slideRatio;
+            var getSlideFactor = function(dim) {
+                return this.map.getSize()[dim] * slideRatio;
+            };
+        }
+
+        btn.getSlideFactor = getSlideFactor;
 
         //we want to remember/reference the outer div
         this.buttons.push(btn);
@@ -180,16 +203,16 @@ OpenLayers.Control.PanZoom = OpenLayers.Class(OpenLayers.Control, {
 
         switch (this.action) {
             case "panup": 
-                this.map.pan(0, -this.slideFactor);
+                this.map.pan(0, -this.getSlideFactor("h"));
                 break;
             case "pandown": 
-                this.map.pan(0, this.slideFactor);
+                this.map.pan(0, this.getSlideFactor("h"));
                 break;
             case "panleft": 
-                this.map.pan(-this.slideFactor, 0);
+                this.map.pan(-this.getSlideFactor("w"), 0);
                 break;
             case "panright": 
-                this.map.pan(this.slideFactor, 0);
+                this.map.pan(this.getSlideFactor("w"), 0);
                 break;
             case "zoomin": 
                 this.map.zoomIn(); 
diff --git a/tests/Control/PanZoom.html b/tests/Control/PanZoom.html
index 65fb84e623..1f2deec0ea 100644
--- a/tests/Control/PanZoom.html
+++ b/tests/Control/PanZoom.html
@@ -138,6 +138,56 @@
         }
     }
 
+    function test_slideRatio(t) {
+        t.plan(4);
+
+        var control = new OpenLayers.Control.PanZoom({
+            slideRatio: .5
+        });
+
+        var map = new OpenLayers.Map();
+
+        map.addControl(control);
+        control.draw();
+        control.activate();
+
+        map.getSize = function() {
+            return {
+                w: 250,
+                h: 100
+            }
+        };
+
+        var delta, dir;
+        var evt = {which: 1}; // a fake left click
+        var buttons = control.buttons;
+        map.pan = function(dx, dy){
+            t.eq([dx,dy],delta,"Panning " + dir + " sets right delta with slideRatio");
+        };
+
+        //up
+        var delta = [0, -50];
+        var dir = "up";
+        control.buttonDown.call(buttons[0], evt);
+        
+        //left
+        var delta = [-125, 0];
+        var dir = "left";
+        control.buttonDown.call(buttons[1], evt);
+        
+        //right
+        var delta = [125, 0];
+        var dir = "right";
+        control.buttonDown.call(buttons[2], evt);
+        
+        //down
+        var delta = [0, 50];
+        var dir = "down";
+        control.buttonDown.call(buttons[3], evt);
+        
+        map.destroy();
+    }
+
     function simulateClick(wnd, elem) {
       var evt = wnd.document.createEvent("MouseEvents");
       evt.initMouseEvent("mousedown", true, true, wnd, 0, 0, 0, 0, 0, false, false, false, false, 0, null);