update manhattan grid example

examples/manhattan_grid/js/example.js

@@ -8,7 +8,7 @@ Avenue A) and Zero St (a.k.a. Houston St). Avenues east of Zero Ave, just as
 Streets south of Zero St, have negative numbers. Broadway, which will split not
 only Manhattan but the entire globe into an eastern and a western hemisphere,
 retains its orientation, but is adjusted slightly so that it originates at the
-intersection of Zero & Zero. From there, Broadway, Zero Ave and Zero Street
+intersection of Zero & Zero. From there, Broadway, Zero Avenue and Zero Street
 continue as perfectly straight equatorial lines. All three will intersect once
 more, exactly halfway, in the Indian Ocean, (southwest of Australia), at the
 point furthest from Manhattan.<br><br>
@@ -16,9 +16,9 @@ As subsequent avenues remain exactly parallel to Zero Ave, and subsequent
 streets exactly parallel to Zero St, they form smaller and smaller circles
 around the globe. The northernmost and southernmost streets are small circles
 in Central Asia (east of the Caspian Sea) and the southern Pacific (near Easter
-Island), the westernmost and easternmost avenues are circles in the North
+Island), the westernmost and easternmost avenues small circles in the North
 Pacific (west of Hawaii) and the South Atlantic (near St. Helena). These four
-extreme points are the North Pole, South Pole, West Pole and East pole of the
+extreme points are the North Pole, South Pole, West Pole and East Pole of the
 coordinate system.
 */
 
@@ -28,10 +28,9 @@ coordinate system.
 Include the Image module.
 */
 Ox.load('Image', function() {
-    //'Etoile': {lat: 48.87377, lng: 2.29505}
 
         /*
-        Ox.EARTH_CIRCUMFERENCE (40075016.68557849) is a built-in constant
+        Ox.EARTH_CIRCUMFERENCE (40075016.68557849) is a built-in constant.
         */
     var C = Ox.EARTH_CIRCUMFERENCE,
         /*
@@ -58,8 +57,8 @@ Ox.load('Image', function() {
         Ox.getBearing returns the bearing, in degrees, from one lat/lng pair to
         another. To make sure that avenues and streets cross at an exact right
         angle, we first calculate the bearing of a line that cuts the upper
-        western quadrant of Columbus Circle in half, then subtract 45 degrees
-        for the direction of the avenues and add 45 degrees for the direction
+        western quadrant of Columbus Circle in half, then add 45 degrees for
+        the direction of the avenues and subtract 45 degrees for the direction
         of the streets.
         */
         bearing = (
@@ -67,6 +66,7 @@ Ox.load('Image', function() {
             + Ox.getBearing(points['5 & 59'], points['8 & 59'])
         ) / 2 + 180,
         bearings = {
+            // fixme: Ox.mod ?
             avenues: (bearing + 45) % 360,
             streets: (bearing - 45) % 360
         },
@@ -120,8 +120,8 @@ Ox.load('Image', function() {
         bearings.streets
     );
     /*
-    The second intersection of 0th Ave, 0th St and Broadway is half of the
-    Earth's circumference away from the first one, in any direction.
+    The second intersection of Zero Avenue, Zero Street and Broadway is half of
+    the Earth's circumference away from the first one, in any direction.
     */
     points['-0 & -0'] = Ox.getPoint(
         points['0 & 0'],
@@ -130,12 +130,12 @@ Ox.load('Image', function() {
     );
     /*
     Now that we have constructed the origin, we can calculate the bearing of
-    Broadway, which runs from 0th & 0th through Columbus Circle.
+    Broadway, which runs from Zero & Zero through Columbus Circle.
     */
     bearings.broadway = Ox.getBearing(points['0 & 0'], points['8 & 59']),
     /*
     Also, we can construct the poles, each of which is a quarter of Earth's
-    circumference away from 0th & 0th.
+    circumference away from Zero & Zero.
     */
     poles = {
         north: Ox.getPoint(points['0 & 0'], C / 4, bearings.avenues),
@@ -161,8 +161,8 @@ Ox.load('Image', function() {
     /*
     Now we calculate circles for Broadway, Avenues and Streets. Ox.getCircle
     returns an array of lat/lng pairs that form a circle around a given point,
-    with a given radius and a given precision (the circle will have
-    <code>Math.pow(2, precision)</code> segments). 
+    with a given radius and a given precision, so that the circle will have
+    <code>Math.pow(2, precision)</code> segments. 
     */
     lines = {
         /*
@@ -232,7 +232,7 @@ Ox.load('Image', function() {
     /*
     <code>getASByLatLng</code> takes lat/lng and returns avenue/street. To
     compute the avenue, we subtract the point's distance from the West Pole, in
-    avenues, from the total number of avenues, to compute the street, we
+    avenues, from the total number of avenues. To compute the street, we
     subtract the point's distance from the North Pole, in avenues, from the
     total number of streets. We also return the bearing of the avenues at this
     point (which form a right angle with the line from the point to the West