Add repeat property to po.url.

True by default. Can be set to false to disable column wrap-around.

examples/cloudmade/pale-dawn.js

@@ -9,6 +9,7 @@ map.add(po.image()
     .url(po.url("http://{S}tile.cloudmade.com"
     + "/1a1b06b230af4efdbb989ea99e9841af" // http://cloudmade.com/register
     + "/998/256/{Z}/{X}/{Y}.png")
+    .repeat(false)
     .hosts(["a.", "b.", "c.", ""])));
 
 map.add(po.compass()

polymaps.js

@@ -2,7 +2,7 @@ if (!org) var org = {};
 if (!org.polymaps) org.polymaps = {};
 (function(po){
 
-  po.version = "2.3.0"; // semver.org
+  po.version = "2.3+1.0"; // not semver!
 
   var zero = {x: 0, y: 0};
 po.ns = {
@@ -182,12 +182,18 @@ po.cache = function(load, unload) {
   return cache;
 };
 po.url = function(template) {
-  var hosts = [];
+  var hosts = [],
+      repeat = true;
 
   function format(c) {
     var max = c.zoom < 0 ? 1 : 1 << c.zoom,
-        column = c.column % max;
-    if (column < 0) column += max;
+        column = c.column;
+    if (repeat) {
+      column = c.column % max;
+      if (column < 0) column += max;
+    } else if ((column < 0) || (column >= max)) {
+      return "about:blank";
+    }
     return template.replace(/{(.)}/g, function(s, v) {
       switch (v) {
         case "S": return hosts[(Math.abs(c.zoom) + c.row + column) % hosts.length];
@@ -220,6 +226,12 @@ po.url = function(template) {
     return format;
   };
 
+  format.repeat = function(x) {
+    if (!arguments.length) return repeat;
+    repeat = x;
+    return format;
+  };
+
   return format;
 };
 po.dispatch = function(that) {