Reinstate d3.geo.greatCircle.polyline.

For backwards compatibility.

d3.geo.js

@@ -622,15 +622,22 @@ function d3_geo_boundsPolygon(o, f) {
 }
 // From http://williams.best.vwh.net/avform.htm#Intermediate
 d3.geo.greatCircle = function() {
-  var coordinates = Object,
+  var source = d3_geo_greatCircleSource,
+      target = d3_geo_greatCircleTarget,
+      coordinates = Object, // for use with polyline
       precision = 1,
       radius = d3_geo_earthRadius;
   // TODO: breakAtDateLine?
 
   function greatCircle(d, i) {
-    return d3_geo_greatCirclePath(coordinates.call(this, d, i), precision);
+    return d3_geo_greatCirclePath([
+      source.call(this, d, i), target.call(this, d, i)], precision);
   }
 
+  greatCircle.polyline = function(d, i) {
+    return d3_geo_greatCirclePath(coordinates.call(this, d, i), precision);
+  };
+
   greatCircle.coordinates = function(x) {
     if (!arguments.length) return coordinates;
     coordinates = x;
@@ -651,29 +658,16 @@ d3.geo.greatCircle = function() {
 
   // Haversine formula for great-circle distance.
   greatCircle.distance = function(d, i) {
-    d = coordinates.call(this, d, i);
-    if (d.length < 2) return NaN;
-
-    var from = d[0],
-        to,
+    var from = source.call(this, d, i),
+        to = target.call(this, d, i),
         x0 = from[0] * d3_radians,
         y0 = from[1] * d3_radians,
-        n = d.length,
-        i = 0,
-        s = 0;
-
-    while (++i < n) {
-      to = d[i];
-      var x1 = to[0] * d3_radians,
-          y1 = to[1] * d3_radians,
-          sy = Math.sin((y1 - y0) / 2),
-          sx = Math.sin((x1 - x0) / 2),
-          a = sy * sy + Math.cos(y0) * Math.cos(y1) * sx * sx;
-      x0 = x1;
-      y0 = y1;
-      s += radius * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
-    }
-    return s;
+        x1 = to[0] * d3_radians,
+        y1 = to[1] * d3_radians,
+        sy = Math.sin((y1 - y0) / 2),
+        sx = Math.sin((x1 - x0) / 2),
+        a = sy * sy + Math.cos(y0) * Math.cos(y1) * sx * sx;
+    return radius * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
   };
 
   return greatCircle;
@@ -727,6 +721,14 @@ function d3_geo_greatCirclePath(coordinates, precision) {
 
   return path;
 }
+
+function d3_geo_greatCircleSource(d) {
+  return d.source;
+}
+
+function d3_geo_greatCircleTarget(d) {
+  return d.target;
+}
 d3.geo.clip = function() {
   var origin = [0, 0],
       angle = 90,
@@ -790,9 +792,7 @@ d3.geo.clip = function() {
   return clip;
 }
 
-var d3_geo_clipGreatCircle = d3.geo.greatCircle().coordinates(function(d) {
-  return [d.source, d.target];
-});
+var d3_geo_clipGreatCircle = d3.geo.greatCircle();
 
 function d3_geo_clipIntersect(from, to, f) {
   var x0 = from[0] * d3_radians,

examples/azimuthal/azimuthal.html

@@ -91,7 +91,7 @@ <h3>Azimuthal Projection</h3>
 $("#mode").change(function() {
   var mode = $(this).val();
   xy.mode(mode);
-  path.clip(mode === "gnomonic" ? clip : circle);
+  path.clip(mode === "gnomonic" ? clip : circle.polyline);
   refresh(500);
 });
 

examples/azimuthal/azimuthal.js

@@ -1,7 +1,7 @@
 var xy = d3.geo.azimuthal().scale(240).mode("stereographic"),
     clip = d3.geo.clip().angle(89),
     circle = d3.geo.greatCircle().precision(10).coordinates(clip),
-    path = d3.geo.path().projection(xy).clip(circle),
+    path = d3.geo.path().projection(xy).clip(circle.polyline),
     svg = d3.select("body").append("svg:svg");
 
 d3.json("../data/world-countries.json", function(collection) {

src/geo/clip.js

@@ -61,9 +61,7 @@ d3.geo.clip = function() {
   return clip;
 }
 
-var d3_geo_clipGreatCircle = d3.geo.greatCircle().coordinates(function(d) {
-  return [d.source, d.target];
-});
+var d3_geo_clipGreatCircle = d3.geo.greatCircle();
 
 function d3_geo_clipIntersect(from, to, f) {
   var x0 = from[0] * d3_radians,

src/geo/greatCircle.js

@@ -1,14 +1,21 @@
 // From http://williams.best.vwh.net/avform.htm#Intermediate
 d3.geo.greatCircle = function() {
-  var coordinates = Object,
+  var source = d3_geo_greatCircleSource,
+      target = d3_geo_greatCircleTarget,
+      coordinates = Object, // for use with polyline
       precision = 1,
       radius = d3_geo_earthRadius;
   // TODO: breakAtDateLine?
 
   function greatCircle(d, i) {
-    return d3_geo_greatCirclePath(coordinates.call(this, d, i), precision);
+    return d3_geo_greatCirclePath([
+      source.call(this, d, i), target.call(this, d, i)], precision);
   }
 
+  greatCircle.polyline = function(d, i) {
+    return d3_geo_greatCirclePath(coordinates.call(this, d, i), precision);
+  };
+
   greatCircle.coordinates = function(x) {
     if (!arguments.length) return coordinates;
     coordinates = x;
@@ -29,29 +36,16 @@ d3.geo.greatCircle = function() {
 
   // Haversine formula for great-circle distance.
   greatCircle.distance = function(d, i) {
-    d = coordinates.call(this, d, i);
-    if (d.length < 2) return NaN;
-
-    var from = d[0],
-        to,
+    var from = source.call(this, d, i),
+        to = target.call(this, d, i),
         x0 = from[0] * d3_radians,
         y0 = from[1] * d3_radians,
-        n = d.length,
-        i = 0,
-        s = 0;
-
-    while (++i < n) {
-      to = d[i];
-      var x1 = to[0] * d3_radians,
-          y1 = to[1] * d3_radians,
-          sy = Math.sin((y1 - y0) / 2),
-          sx = Math.sin((x1 - x0) / 2),
-          a = sy * sy + Math.cos(y0) * Math.cos(y1) * sx * sx;
-      x0 = x1;
-      y0 = y1;
-      s += radius * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
-    }
-    return s;
+        x1 = to[0] * d3_radians,
+        y1 = to[1] * d3_radians,
+        sy = Math.sin((y1 - y0) / 2),
+        sx = Math.sin((x1 - x0) / 2),
+        a = sy * sy + Math.cos(y0) * Math.cos(y1) * sx * sx;
+    return radius * 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
   };
 
   return greatCircle;
@@ -105,3 +99,11 @@ function d3_geo_greatCirclePath(coordinates, precision) {
 
   return path;
 }
+
+function d3_geo_greatCircleSource(d) {
+  return d.source;
+}
+
+function d3_geo_greatCircleTarget(d) {
+  return d.target;
+}

test/geo/greatCircle-test.js

@@ -13,14 +13,14 @@ suite.addBatch({
       return d3.geo.greatCircle().precision(7.5);
     },
     "distance": function(circle) {
-      assert.equal(circle.distance([[0, 0], [0, 0]]), 0);
-      assert.inDelta(circle.distance([
-        [118 + 24 / 60, 33 + 57 / 60],
-        [ 73 + 47 / 60, 40 + 38 / 60]
-      ]), 3973, .5);
+      assert.equal(circle.distance({source: [0, 0], target: [0, 0]}), 0);
+      assert.inDelta(circle.distance({
+        source: [118 + 24 / 60, 33 + 57 / 60],
+        target: [ 73 + 47 / 60, 40 + 38 / 60]
+      }), 3973, .5);
     },
     "geodesic": function(circle) {
-      assert.inDelta(circle([[5, 52], [-120, 37]]), [
+      assert.inDelta(circle.polyline([[5, 52], [-120, 37]]), [
         [   5,        52      ],
         [  -3.805036, 57.05083],
         [ -15.122869, 61.30118],