diff --git a/sanitiser/wrap.js b/sanitiser/wrap.js
index f1a482e5..c89088e7 100644
--- a/sanitiser/wrap.js
+++ b/sanitiser/wrap.js
@@ -1,23 +1,37 @@
 
 /**
   normalize co-ordinates that lie outside of the normal ranges.
+
+  longitude wrapping simply requires adding +- 360 to the value until it comes
+  in to range.
+
+  for the latitude values we need to flip the longitude whenever the latitude
+  crosses a pole.
 **/
 
+
 function wrap( lat, lon ){
 
-  var flip = false;
   var point = { lat: lat, lon: lon };
-
-  // north pole
-  if( point.lat > 90 ){
-    point.lat = 90 - point.lat % 90;
-    point.lon += 180;
-  }
-
-  // south pole
-  else if( point.lat < -90 ){
-    point.lat = -90 - point.lat % 90;
-    point.lon += 180;
+  var quadrant = Math.floor( Math.abs(lat) / 90) % 4;
+  var pole = ( lat > 0 ) ? 90 : -90;
+  var offset = lat % 90;
+
+  switch( quadrant ){
+    case 0:
+      point.lat = offset;
+      break;
+    case 1:
+      point.lat = pole - offset;
+      point.lon += 180;
+      break;
+    case 2:
+      point.lat = -offset;
+      point.lon += 180;
+      break;
+    case 3:
+      point.lat = -pole + offset;
+      break;
   }
 
   // reduce lon
diff --git a/test/unit/sanitiser/_geo_common.js b/test/unit/sanitiser/_geo_common.js
index d8e174d3..93ec5d11 100644
--- a/test/unit/sanitiser/_geo_common.js
+++ b/test/unit/sanitiser/_geo_common.js
@@ -12,60 +12,61 @@ module.exports.tests.interface = function(test, common) {
   });
 };
 
+// @note: for better coverage see unit tests for 'wrap.js'.
 module.exports.tests.wrapping = function(test, common) {
   test('control - no wrapping required', function (t) {
     var clean = {};
     var params = {
-      'point.lat': 40.7,
-      'point.lon': -73.9
+      'point.lat': +1.1,
+      'point.lon': -1.1
     };
     sanitize.sanitize_point( 'point', clean, params, false );
-    t.equal(clean['point.lat'], params['point.lat']);
-    t.equal(clean['point.lon'], params['point.lon']);
+    t.equal(clean['point.lat'], +1.1, 'not changed');
+    t.equal(clean['point.lon'], -1.1, 'not changed');
     t.end();
   });
   test('positive longitude wrapping', function (t) {
     var clean = {};
     var params = {
-      'point.lat': 40.7,
-      'point.lon': 195.1
+      'point.lat': +1.1,
+      'point.lon': +181.1
     };
     sanitize.sanitize_point( 'point', clean, params, false );
-    t.equal(clean['point.lat'], 40.7);
-    t.equal(clean['point.lon'], -164.9);
+    t.equal(clean['point.lat'], +1.1, 'not changed');
+    t.equal(clean['point.lon'], -178.9, 'equal to (-180 + 1.1)');
     t.end();
   });
   test('negative longitude wrapping', function (t) {
     var clean = {};
     var params = {
-      'point.lat': 40.7,
-      'point.lon': -195.1
+      'point.lat': -1.1,
+      'point.lon': -181.1
     };
     sanitize.sanitize_point( 'point', clean, params, false );
-    t.equal(clean['point.lat'], 40.7);
-    t.equal(clean['point.lon'], 164.9);
+    t.equal(clean['point.lat'], -1.1, 'not changed');
+    t.equal(clean['point.lon'], +178.9, 'equal to (+180 - 1.1)');
     t.end();
   });
   test('positive latitudinal wrapping', function (t) {
     var clean = {};
     var params = {
-      'point.lat': 98.1,
-      'point.lon': -73.9
+      'point.lat': 91.1,
+      'point.lon': 1.1
     };
     sanitize.sanitize_point( 'point', clean, params, false );
-    t.equal(clean['point.lat'], 81.9);
-    t.equal(clean['point.lon'], 106.1);
+    t.equal(clean['point.lat'], +88.9, 'equal to (+90 - 1.1)');
+    t.equal(clean['point.lon'], -178.9, 'equal to (-180 - 1.1)'); // polar flip
     t.end();
   });
   test('negative latitudinal wrapping', function (t) {
     var clean = {};
     var params = {
-      'point.lat': -98.1,
-      'point.lon': -73.9
+      'point.lat': -91.1,
+      'point.lon': -1.1
     };
     sanitize.sanitize_point( 'point', clean, params, false );
-    t.equal(clean['point.lat'], -81.9);
-    t.equal(clean['point.lon'], 106.1);
+    t.equal(clean['point.lat'], -88.9, 'equal to (-90 + 1.1)');
+    t.equal(clean['point.lon'], +178.9, 'equal to (+180 - 1.1)'); // polar flip
     t.end();
   });
 };
diff --git a/test/unit/sanitiser/wrap.js b/test/unit/sanitiser/wrap.js
index 73e2ec0e..ea9a75a5 100644
--- a/test/unit/sanitiser/wrap.js
+++ b/test/unit/sanitiser/wrap.js
@@ -3,59 +3,179 @@ var wrap = require('../../../sanitiser/wrap');
 
 module.exports.tests = {};
 
-module.exports.tests.wrapping = function(test, common) {
+module.exports.tests.control = function(test, common) {
   test('control - no wrapping required', function (t) {
     var norm = wrap(55.555, 22.222);
     t.equal(norm.lat, 55.555);
     t.equal(norm.lon, 22.222);
     t.end();
   });
-  test('positive longitude wrapping', function (t) {
+};
+
+module.exports.tests.latitude_positive = function(test, common) {
+  test('positive latitude wrapping - 1 degree', function (t) {
+    var norm = wrap(1, 0);
+    t.equal(norm.lat, 1);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('positive latitude wrapping - 91 degrees', function (t) {
+    var norm = wrap(91, 0);
+    t.equal(norm.lat, 89);
+    t.equal(norm.lon, 180);
+    t.end();
+  });
+  test('positive latitude wrapping - 181 degrees', function (t) {
+    var norm = wrap(181, 0);
+    t.equal(norm.lat, -1);
+    t.equal(norm.lon, 180);
+    t.end();
+  });
+  test('positive latitude wrapping - 271 degrees', function (t) {
+    var norm = wrap(271, 0);
+    t.equal(norm.lat, -89);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('positive latitude wrapping - 361 degrees', function (t) {
+    var norm = wrap(361, 0);
+    t.equal(norm.lat, 1);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('positive latitude wrapping - 631 degrees', function (t) {
+    var norm = wrap(631, 0);
+    t.equal(norm.lat, -89);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('positive latitude wrapping - 721 degrees', function (t) {
+    var norm = wrap(721, 0);
+    t.equal(norm.lat, 1);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+};
+
+module.exports.tests.latitude_negative = function(test, common) {
+  test('negative latitude wrapping - 1 degree', function (t) {
+    var norm = wrap(-1, 0);
+    t.equal(norm.lat, -1);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('negative latitude wrapping - 91 degrees', function (t) {
+    var norm = wrap(-91, 0);
+    t.equal(norm.lat, -89);
+    t.equal(norm.lon, 180);
+    t.end();
+  });
+  test('negative latitude wrapping - 181 degrees', function (t) {
+    var norm = wrap(-181, 0);
+    t.equal(norm.lat, 1);
+    t.equal(norm.lon, 180);
+    t.end();
+  });
+  test('negative latitude wrapping - 271 degrees', function (t) {
+    var norm = wrap(-271, 0);
+    t.equal(norm.lat, 89);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('negative latitude wrapping - 361 degrees', function (t) {
+    var norm = wrap(-361, 0);
+    t.equal(norm.lat, -1);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('negative latitude wrapping - 631 degrees', function (t) {
+    var norm = wrap(-631, 0);
+    t.equal(norm.lat, 89);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+  test('positive latitude wrapping - 721 degrees', function (t) {
+    var norm = wrap(721, 0);
+    t.equal(norm.lat, 1);
+    t.equal(norm.lon, 0);
+    t.end();
+  });
+};
+
+module.exports.tests.longitude_positive = function(test, common) {
+  test('positive longitude wrapping - 1 degree', function (t) {
+    var norm = wrap(0, 1);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, 1);
+    t.end();
+  });
+  test('positive longitude wrapping - 181 degrees', function (t) {
     var norm = wrap(0, 181);
     t.equal(norm.lat, 0);
     t.equal(norm.lon, -179);
     t.end();
   });
-  test('positive longitude wrapping (double)', function (t) {
-    var norm = wrap(0, 541);
+  test('positive longitude wrapping - 271 degrees', function (t) {
+    var norm = wrap(0, 271);
     t.equal(norm.lat, 0);
-    t.equal(norm.lon, -179);
+    t.equal(norm.lon, -89);
     t.end();
   });
-  test('negative longitude wrapping', function (t) {
-    var norm = wrap(0, -181);
+  test('positive longitude wrapping - 361 degrees', function (t) {
+    var norm = wrap(0, 361);
     t.equal(norm.lat, 0);
-    t.equal(norm.lon, 179);
+    t.equal(norm.lon, 1);
+    t.end();
+  });
+  test('positive longitude wrapping - 631 degrees', function (t) {
+    var norm = wrap(0, 631);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, -89);
     t.end();
   });
-  test('negative longitude wrapping (double)', function (t) {
-    var norm = wrap(0, -541);
+  test('positive longitude wrapping - 721 degrees', function (t) {
+    var norm = wrap(0, 721);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, 1);
+    t.end();
+  });
+};
+
+module.exports.tests.longitude_negative = function(test, common) {
+  test('negative longitude wrapping - 1 degree', function (t) {
+    var norm = wrap(0, -1);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, -1);
+    t.end();
+  });
+  test('negative longitude wrapping - 181 degrees', function (t) {
+    var norm = wrap(0, -181);
     t.equal(norm.lat, 0);
     t.equal(norm.lon, 179);
     t.end();
   });
-  test('positive latitudinal wrapping', function (t) {
-    var norm = wrap(91, 0);
-    t.equal(norm.lat, 89);
-    t.equal(norm.lon, 180);
+  test('negative longitude wrapping - 271 degrees', function (t) {
+    var norm = wrap(0, -271);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, 89);
     t.end();
   });
-  test('positive latitudinal wrapping (double)', function (t) {
-    var norm = wrap(271, 0);
-    t.equal(norm.lat, 89);
-    t.equal(norm.lon, 180);
+  test('negative longitude wrapping - 361 degrees', function (t) {
+    var norm = wrap(0, -361);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, -1);
     t.end();
   });
-  test('negative latitudinal wrapping', function (t) {
-    var norm = wrap(-91, 0);
-    t.equal(norm.lat, -89);
-    t.equal(norm.lon, 180);
+  test('negative longitude wrapping - 631 degrees', function (t) {
+    var norm = wrap(0, -631);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, 89);
     t.end();
   });
-  test('negative latitudinal wrapping (double)', function (t) {
-    var norm = wrap(-271, 0);
-    t.equal(norm.lat, -89);
-    t.equal(norm.lon, 180);
+  test('negative longitude wrapping - 721 degrees', function (t) {
+    var norm = wrap(0, -721);
+    t.equal(norm.lat, 0);
+    t.equal(norm.lon, -1);
     t.end();
   });
 };