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diff --git a/gstudio/static/gstudio/js/d3.geo.js b/gstudio/static/gstudio/js/d3.geo.js new file mode 100644 index 00000000..2b402525 --- /dev/null +++ b/gstudio/static/gstudio/js/d3.geo.js @@ -0,0 +1,938 @@ +(function(){d3.geo = {}; + +var d3_geo_radians = Math.PI / 180; +// TODO clip input coordinates on opposite hemisphere +d3.geo.azimuthal = function() { + var mode = "orthographic", // or stereographic, gnomonic, equidistant or equalarea + origin, + scale = 200, + translate = [480, 250], + x0, + y0, + cy0, + sy0; + + function azimuthal(coordinates) { + var x1 = coordinates[0] * d3_geo_radians - x0, + y1 = coordinates[1] * d3_geo_radians, + cx1 = Math.cos(x1), + sx1 = Math.sin(x1), + cy1 = Math.cos(y1), + sy1 = Math.sin(y1), + cc = mode !== "orthographic" ? sy0 * sy1 + cy0 * cy1 * cx1 : null, + c, + k = mode === "stereographic" ? 1 / (1 + cc) + : mode === "gnomonic" ? 1 / cc + : mode === "equidistant" ? (c = Math.acos(cc), c ? c / Math.sin(c) : 0) + : mode === "equalarea" ? Math.sqrt(2 / (1 + cc)) + : 1, + x = k * cy1 * sx1, + y = k * (sy0 * cy1 * cx1 - cy0 * sy1); + return [ + scale * x + translate[0], + scale * y + translate[1] + ]; + } + + azimuthal.invert = function(coordinates) { + var x = (coordinates[0] - translate[0]) / scale, + y = (coordinates[1] - translate[1]) / scale, + p = Math.sqrt(x * x + y * y), + c = mode === "stereographic" ? 2 * Math.atan(p) + : mode === "gnomonic" ? Math.atan(p) + : mode === "equidistant" ? p + : mode === "equalarea" ? 2 * Math.asin(.5 * p) + : Math.asin(p), + sc = Math.sin(c), + cc = Math.cos(c); + return [ + (x0 + Math.atan2(x * sc, p * cy0 * cc + y * sy0 * sc)) / d3_geo_radians, + Math.asin(cc * sy0 - (p ? (y * sc * cy0) / p : 0)) / d3_geo_radians + ]; + }; + + azimuthal.mode = function(x) { + if (!arguments.length) return mode; + mode = x + ""; + return azimuthal; + }; + + azimuthal.origin = function(x) { + if (!arguments.length) return origin; + origin = x; + x0 = origin[0] * d3_geo_radians; + y0 = origin[1] * d3_geo_radians; + cy0 = Math.cos(y0); + sy0 = Math.sin(y0); + return azimuthal; + }; + + azimuthal.scale = function(x) { + if (!arguments.length) return scale; + scale = +x; + return azimuthal; + }; + + azimuthal.translate = function(x) { + if (!arguments.length) return translate; + translate = [+x[0], +x[1]]; + return azimuthal; + }; + + return azimuthal.origin([0, 0]); +}; +// Derived from Tom Carden's Albers implementation for Protovis. +// http://gist.github.com/476238 +// http://mathworld.wolfram.com/AlbersEqual-AreaConicProjection.html + +d3.geo.albers = function() { + var origin = [-98, 38], + parallels = [29.5, 45.5], + scale = 1000, + translate = [480, 250], + lng0, // d3_geo_radians * origin[0] + n, + C, + p0; + + function albers(coordinates) { + var t = n * (d3_geo_radians * coordinates[0] - lng0), + p = Math.sqrt(C - 2 * n * Math.sin(d3_geo_radians * coordinates[1])) / n; + return [ + scale * p * Math.sin(t) + translate[0], + scale * (p * Math.cos(t) - p0) + translate[1] + ]; + } + + albers.invert = function(coordinates) { + var x = (coordinates[0] - translate[0]) / scale, + y = (coordinates[1] - translate[1]) / scale, + p0y = p0 + y, + t = Math.atan2(x, p0y), + p = Math.sqrt(x * x + p0y * p0y); + return [ + (lng0 + t / n) / d3_geo_radians, + Math.asin((C - p * p * n * n) / (2 * n)) / d3_geo_radians + ]; + }; + + function reload() { + var phi1 = d3_geo_radians * parallels[0], + phi2 = d3_geo_radians * parallels[1], + lat0 = d3_geo_radians * origin[1], + s = Math.sin(phi1), + c = Math.cos(phi1); + lng0 = d3_geo_radians * origin[0]; + n = .5 * (s + Math.sin(phi2)); + C = c * c + 2 * n * s; + p0 = Math.sqrt(C - 2 * n * Math.sin(lat0)) / n; + return albers; + } + + albers.origin = function(x) { + if (!arguments.length) return origin; + origin = [+x[0], +x[1]]; + return reload(); + }; + + albers.parallels = function(x) { + if (!arguments.length) return parallels; + parallels = [+x[0], +x[1]]; + return reload(); + }; + + albers.scale = function(x) { + if (!arguments.length) return scale; + scale = +x; + return albers; + }; + + albers.translate = function(x) { + if (!arguments.length) return translate; + translate = [+x[0], +x[1]]; + return albers; + }; + + return reload(); +}; + +// A composite projection for the United States, 960x500. The set of standard +// parallels for each region comes from USGS, which is published here: +// http://egsc.usgs.gov/isb/pubs/MapProjections/projections.html#albers +// TODO allow the composite projection to be rescaled? +d3.geo.albersUsa = function() { + var lower48 = d3.geo.albers(); + + var alaska = d3.geo.albers() + .origin([-160, 60]) + .parallels([55, 65]); + + var hawaii = d3.geo.albers() + .origin([-160, 20]) + .parallels([8, 18]); + + var puertoRico = d3.geo.albers() + .origin([-60, 10]) + .parallels([8, 18]); + + function albersUsa(coordinates) { + var lon = coordinates[0], + lat = coordinates[1]; + return (lat > 50 ? alaska + : lon < -140 ? hawaii + : lat < 21 ? puertoRico + : lower48)(coordinates); + } + + albersUsa.scale = function(x) { + if (!arguments.length) return lower48.scale(); + lower48.scale(x); + alaska.scale(x * .6); + hawaii.scale(x); + puertoRico.scale(x * 1.5); + return albersUsa.translate(lower48.translate()); + }; + + albersUsa.translate = function(x) { + if (!arguments.length) return lower48.translate(); + var dz = lower48.scale() / 1000, + dx = x[0], + dy = x[1]; + lower48.translate(x); + alaska.translate([dx - 400 * dz, dy + 170 * dz]); + hawaii.translate([dx - 190 * dz, dy + 200 * dz]); + puertoRico.translate([dx + 580 * dz, dy + 430 * dz]); + return albersUsa; + }; + + return albersUsa.scale(lower48.scale()); +}; +d3.geo.bonne = function() { + var scale = 200, + translate = [480, 250], + x0, // origin longitude in radians + y0, // origin latitude in radians + y1, // parallel latitude in radians + c1; // cot(y1) + + function bonne(coordinates) { + var x = coordinates[0] * d3_geo_radians - x0, + y = coordinates[1] * d3_geo_radians - y0; + if (y1) { + var p = c1 + y1 - y, E = x * Math.cos(y) / p; + x = p * Math.sin(E); + y = p * Math.cos(E) - c1; + } else { + x *= Math.cos(y); + y *= -1; + } + return [ + scale * x + translate[0], + scale * y + translate[1] + ]; + } + + bonne.invert = function(coordinates) { + var x = (coordinates[0] - translate[0]) / scale, + y = (coordinates[1] - translate[1]) / scale; + if (y1) { + var c = c1 + y, p = Math.sqrt(x * x + c * c); + y = c1 + y1 - p; + x = x0 + p * Math.atan2(x, c) / Math.cos(y); + } else { + y *= -1; + x /= Math.cos(y); + } + return [ + x / d3_geo_radians, + y / d3_geo_radians + ]; + }; + + // 90° for Werner, 0° for Sinusoidal + bonne.parallel = function(x) { + if (!arguments.length) return y1 / d3_geo_radians; + c1 = 1 / Math.tan(y1 = x * d3_geo_radians); + return bonne; + }; + + bonne.origin = function(x) { + if (!arguments.length) return [x0 / d3_geo_radians, y0 / d3_geo_radians]; + x0 = x[0] * d3_geo_radians; + y0 = x[1] * d3_geo_radians; + return bonne; + }; + + bonne.scale = function(x) { + if (!arguments.length) return scale; + scale = +x; + return bonne; + }; + + bonne.translate = function(x) { + if (!arguments.length) return translate; + translate = [+x[0], +x[1]]; + return bonne; + }; + + return bonne.origin([0, 0]).parallel(45); +}; +d3.geo.equirectangular = function() { + var scale = 500, + translate = [480, 250]; + + function equirectangular(coordinates) { + var x = coordinates[0] / 360, + y = -coordinates[1] / 360; + return [ + scale * x + translate[0], + scale * y + translate[1] + ]; + } + + equirectangular.invert = function(coordinates) { + var x = (coordinates[0] - translate[0]) / scale, + y = (coordinates[1] - translate[1]) / scale; + return [ + 360 * x, + -360 * y + ]; + }; + + equirectangular.scale = function(x) { + if (!arguments.length) return scale; + scale = +x; + return equirectangular; + }; + + equirectangular.translate = function(x) { + if (!arguments.length) return translate; + translate = [+x[0], +x[1]]; + return equirectangular; + }; + + return equirectangular; +}; +d3.geo.mercator = function() { + var scale = 500, + translate = [480, 250]; + + function mercator(coordinates) { + var x = coordinates[0] / 360, + y = -(Math.log(Math.tan(Math.PI / 4 + coordinates[1] * d3_geo_radians / 2)) / d3_geo_radians) / 360; + return [ + scale * x + translate[0], + scale * Math.max(-.5, Math.min(.5, y)) + translate[1] + ]; + } + + mercator.invert = function(coordinates) { + var x = (coordinates[0] - translate[0]) / scale, + y = (coordinates[1] - translate[1]) / scale; + return [ + 360 * x, + 2 * Math.atan(Math.exp(-360 * y * d3_geo_radians)) / d3_geo_radians - 90 + ]; + }; + + mercator.scale = function(x) { + if (!arguments.length) return scale; + scale = +x; + return mercator; + }; + + mercator.translate = function(x) { + if (!arguments.length) return translate; + translate = [+x[0], +x[1]]; + return mercator; + }; + + return mercator; +}; +function d3_geo_type(types, defaultValue) { + return function(object) { + return object && object.type in types ? types[object.type](object) : defaultValue; + }; +} +/** + * Returns a function that, given a GeoJSON object (e.g., a feature), returns + * the corresponding SVG path. The function can be customized by overriding the + * projection. Point features are mapped to circles with a default radius of + * 4.5px; the radius can be specified either as a constant or a function that + * is evaluated per object. + */ +d3.geo.path = function() { + var pointRadius = 4.5, + pointCircle = d3_path_circle(pointRadius), + projection = d3.geo.albersUsa(); + + function path(d, i) { + if (typeof pointRadius === "function") { + pointCircle = d3_path_circle(pointRadius.apply(this, arguments)); + } + return pathType(d) || null; + } + + function project(coordinates) { + return projection(coordinates).join(","); + } + + var pathType = d3_geo_type({ + + FeatureCollection: function(o) { + var path = [], + features = o.features, + i = -1, // features.index + n = features.length; + while (++i < n) path.push(pathType(features[i].geometry)); + return path.join(""); + }, + + Feature: function(o) { + return pathType(o.geometry); + }, + + Point: function(o) { + return "M" + project(o.coordinates) + pointCircle; + }, + + MultiPoint: function(o) { + var path = [], + coordinates = o.coordinates, + i = -1, // coordinates.index + n = coordinates.length; + while (++i < n) path.push("M", project(coordinates[i]), pointCircle); + return path.join(""); + }, + + LineString: function(o) { + var path = ["M"], + coordinates = o.coordinates, + i = -1, // coordinates.index + n = coordinates.length; + while (++i < n) path.push(project(coordinates[i]), "L"); + path.pop(); + return path.join(""); + }, + + MultiLineString: function(o) { + var path = [], + coordinates = o.coordinates, + i = -1, // coordinates.index + n = coordinates.length, + subcoordinates, // coordinates[i] + j, // subcoordinates.index + m; // subcoordinates.length + while (++i < n) { + subcoordinates = coordinates[i]; + j = -1; + m = subcoordinates.length; + path.push("M"); + while (++j < m) path.push(project(subcoordinates[j]), "L"); + path.pop(); + } + return path.join(""); + }, + + Polygon: function(o) { + var path = [], + coordinates = o.coordinates, + i = -1, // coordinates.index + n = coordinates.length, + subcoordinates, // coordinates[i] + j, // subcoordinates.index + m; // subcoordinates.length + while (++i < n) { + subcoordinates = coordinates[i]; + j = -1; + if ((m = subcoordinates.length - 1) > 0) { + path.push("M"); + while (++j < m) path.push(project(subcoordinates[j]), "L"); + path[path.length - 1] = "Z"; + } + } + return path.join(""); + }, + + MultiPolygon: function(o) { + var path = [], + coordinates = o.coordinates, + i = -1, // coordinates index + n = coordinates.length, + subcoordinates, // coordinates[i] + j, // subcoordinates index + m, // subcoordinates.length + subsubcoordinates, // subcoordinates[j] + k, // subsubcoordinates index + p; // subsubcoordinates.length + while (++i < n) { + subcoordinates = coordinates[i]; + j = -1; + m = subcoordinates.length; + while (++j < m) { + subsubcoordinates = subcoordinates[j]; + k = -1; + if ((p = subsubcoordinates.length - 1) > 0) { + path.push("M"); + while (++k < p) path.push(project(subsubcoordinates[k]), "L"); + path[path.length - 1] = "Z"; + } + } + } + return path.join(""); + }, + + GeometryCollection: function(o) { + var path = [], + geometries = o.geometries, + i = -1, // geometries index + n = geometries.length; + while (++i < n) path.push(pathType(geometries[i])); + return path.join(""); + } + + }); + + var areaType = path.area = d3_geo_type({ + + FeatureCollection: function(o) { + var area = 0, + features = o.features, + i = -1, // features.index + n = features.length; + while (++i < n) area += areaType(features[i]); + return area; + }, + + Feature: function(o) { + return areaType(o.geometry); + }, + + Polygon: function(o) { + return polygonArea(o.coordinates); + }, + + MultiPolygon: function(o) { + var sum = 0, + coordinates = o.coordinates, + i = -1, // coordinates index + n = coordinates.length; + while (++i < n) sum += polygonArea(coordinates[i]); + return sum; + }, + + GeometryCollection: function(o) { + var sum = 0, + geometries = o.geometries, + i = -1, // geometries index + n = geometries.length; + while (++i < n) sum += areaType(geometries[i]); + return sum; + } + + }, 0); + + function polygonArea(coordinates) { + var sum = area(coordinates[0]), // exterior ring + i = 0, // coordinates.index + n = coordinates.length; + while (++i < n) sum -= area(coordinates[i]); // holes + return sum; + } + + function polygonCentroid(coordinates) { + var polygon = d3.geom.polygon(coordinates[0].map(projection)), // exterior ring + area = polygon.area(), + centroid = polygon.centroid(area < 0 ? (area *= -1, 1) : -1), + x = centroid[0], + y = centroid[1], + z = area, + i = 0, // coordinates index + n = coordinates.length; + while (++i < n) { + polygon = d3.geom.polygon(coordinates[i].map(projection)); // holes + area = polygon.area(); + centroid = polygon.centroid(area < 0 ? (area *= -1, 1) : -1); + x -= centroid[0]; + y -= centroid[1]; + z -= area; + } + return [x, y, 6 * z]; // weighted centroid + } + + var centroidType = path.centroid = d3_geo_type({ + + // TODO FeatureCollection + // TODO Point + // TODO MultiPoint + // TODO LineString + // TODO MultiLineString + // TODO GeometryCollection + + Feature: function(o) { + return centroidType(o.geometry); + }, + + Polygon: function(o) { + var centroid = polygonCentroid(o.coordinates); + return [centroid[0] / centroid[2], centroid[1] / centroid[2]]; + }, + + MultiPolygon: function(o) { + var area = 0, + coordinates = o.coordinates, + centroid, + x = 0, + y = 0, + z = 0, + i = -1, // coordinates index + n = coordinates.length; + while (++i < n) { + centroid = polygonCentroid(coordinates[i]); + x += centroid[0]; + y += centroid[1]; + z += centroid[2]; + } + return [x / z, y / z]; + } + + }); + + function area(coordinates) { + return Math.abs(d3.geom.polygon(coordinates.map(projection)).area()); + } + + path.projection = function(x) { + projection = x; + return path; + }; + + path.pointRadius = function(x) { + if (typeof x === "function") pointRadius = x; + else { + pointRadius = +x; + pointCircle = d3_path_circle(pointRadius); + } + return path; + }; + + return path; +}; + +function d3_path_circle(radius) { + return "m0," + radius + + "a" + radius + "," + radius + " 0 1,1 0," + (-2 * radius) + + "a" + radius + "," + radius + " 0 1,1 0," + (+2 * radius) + + "z"; +} +/** + * Given a GeoJSON object, returns the corresponding bounding box. The bounding + * box is represented by a two-dimensional array: [[left, bottom], [right, + * top]], where left is the minimum longitude, bottom is the minimum latitude, + * right is maximum longitude, and top is the maximum latitude. + */ +d3.geo.bounds = function(feature) { + var left = Infinity, + bottom = Infinity, + right = -Infinity, + top = -Infinity; + d3_geo_bounds(feature, function(x, y) { + if (x < left) left = x; + if (x > right) right = x; + if (y < bottom) bottom = y; + if (y > top) top = y; + }); + return [[left, bottom], [right, top]]; +}; + +function d3_geo_bounds(o, f) { + if (o.type in d3_geo_boundsTypes) d3_geo_boundsTypes[o.type](o, f); +} + +var d3_geo_boundsTypes = { + Feature: d3_geo_boundsFeature, + FeatureCollection: d3_geo_boundsFeatureCollection, + GeometryCollection: d3_geo_boundsGeometryCollection, + LineString: d3_geo_boundsLineString, + MultiLineString: d3_geo_boundsMultiLineString, + MultiPoint: d3_geo_boundsLineString, + MultiPolygon: d3_geo_boundsMultiPolygon, + Point: d3_geo_boundsPoint, + Polygon: d3_geo_boundsPolygon +}; + +function d3_geo_boundsFeature(o, f) { + d3_geo_bounds(o.geometry, f); +} + +function d3_geo_boundsFeatureCollection(o, f) { + for (var a = o.features, i = 0, n = a.length; i < n; i++) { + d3_geo_bounds(a[i].geometry, f); + } +} + +function d3_geo_boundsGeometryCollection(o, f) { + for (var a = o.geometries, i = 0, n = a.length; i < n; i++) { + d3_geo_bounds(a[i], f); + } +} + +function d3_geo_boundsLineString(o, f) { + for (var a = o.coordinates, i = 0, n = a.length; i < n; i++) { + f.apply(null, a[i]); + } +} + +function d3_geo_boundsMultiLineString(o, f) { + for (var a = o.coordinates, i = 0, n = a.length; i < n; i++) { + for (var b = a[i], j = 0, m = b.length; j < m; j++) { + f.apply(null, b[j]); + } + } +} + +function d3_geo_boundsMultiPolygon(o, f) { + for (var a = o.coordinates, i = 0, n = a.length; i < n; i++) { + for (var b = a[i][0], j = 0, m = b.length; j < m; j++) { + f.apply(null, b[j]); + } + } +} + +function d3_geo_boundsPoint(o, f) { + f.apply(null, o.coordinates); +} + +function d3_geo_boundsPolygon(o, f) { + for (var a = o.coordinates[0], i = 0, n = a.length; i < n; i++) { + f.apply(null, a[i]); + } +} +// TODO breakAtDateLine? + +d3.geo.circle = function() { + var origin = [0, 0], + degrees = 90 - 1e-2, + radians = degrees * d3_geo_radians, + arc = d3.geo.greatArc().target(Object); + + function circle() { + // TODO render a circle as a Polygon + } + + function visible(point) { + return arc.distance(point) < radians; + } + + circle.clip = function(d) { + arc.source(typeof origin === "function" ? origin.apply(this, arguments) : origin); + return clipType(d); + }; + + var clipType = d3_geo_type({ + + FeatureCollection: function(o) { + var features = o.features.map(clipType).filter(Object); + return features && (o = Object.create(o), o.features = features, o); + }, + + Feature: function(o) { + var geometry = clipType(o.geometry); + return geometry && (o = Object.create(o), o.geometry = geometry, o); + }, + + Point: function(o) { + return visible(o.coordinates) && o; + }, + + MultiPoint: function(o) { + var coordinates = o.coordinates.filter(visible); + return coordinates.length && { + type: o.type, + coordinates: coordinates + }; + }, + + LineString: function(o) { + var coordinates = clip(o.coordinates); + return coordinates.length && (o = Object.create(o), o.coordinates = coordinates, o); + }, + + MultiLineString: function(o) { + var coordinates = o.coordinates.map(clip).filter(function(d) { return d.length; }); + return coordinates.length && (o = Object.create(o), o.coordinates = coordinates, o); + }, + + Polygon: function(o) { + var coordinates = o.coordinates.map(clip); + return coordinates[0].length && (o = Object.create(o), o.coordinates = coordinates, o); + }, + + MultiPolygon: function(o) { + var coordinates = o.coordinates.map(function(d) { return d.map(clip); }).filter(function(d) { return d[0].length; }); + return coordinates.length && (o = Object.create(o), o.coordinates = coordinates, o); + }, + + GeometryCollection: function(o) { + var geometries = o.geometries.map(clipType).filter(Object); + return geometries.length && (o = Object.create(o), o.geometries = geometries, o); + } + + }); + + function clip(coordinates) { + var i = -1, + n = coordinates.length, + clipped = [], + p0, + p1, + p2, + d0, + d1; + + while (++i < n) { + d1 = arc.distance(p2 = coordinates[i]); + if (d1 < radians) { + if (p1) clipped.push(d3_geo_greatArcInterpolate(p1, p2)((d0 - radians) / (d0 - d1))); + clipped.push(p2); + p0 = p1 = null; + } else { + p1 = p2; + if (!p0 && clipped.length) { + clipped.push(d3_geo_greatArcInterpolate(clipped[clipped.length - 1], p1)((radians - d0) / (d1 - d0))); + p0 = p1; + } + } + d0 = d1; + } + + if (p1 && clipped.length) { + d1 = arc.distance(p2 = clipped[0]); + clipped.push(d3_geo_greatArcInterpolate(p1, p2)((d0 - radians) / (d0 - d1))); + } + + return resample(clipped); + } + + // Resample coordinates, creating great arcs between each. + function resample(coordinates) { + var i = 0, + n = coordinates.length, + j, + m, + resampled = n ? [coordinates[0]] : coordinates, + resamples, + origin = arc.source(); + + while (++i < n) { + resamples = arc.source(coordinates[i - 1])(coordinates[i]).coordinates; + for (j = 0, m = resamples.length; ++j < m;) resampled.push(resamples[j]); + } + + arc.source(origin); + return resampled; + } + + circle.origin = function(x) { + if (!arguments.length) return origin; + origin = x; + return circle; + }; + + circle.angle = function(x) { + if (!arguments.length) return degrees; + radians = (degrees = +x) * d3_geo_radians; + return circle; + }; + + // Precision is specified in degrees. + circle.precision = function(x) { + if (!arguments.length) return arc.precision(); + arc.precision(x); + return circle; + }; + + return circle; +} +d3.geo.greatArc = function() { + var source = d3_geo_greatArcSource, + target = d3_geo_greatArcTarget, + precision = 6 * d3_geo_radians; + + function greatArc() { + var a = typeof source === "function" ? source.apply(this, arguments) : source, + b = typeof target === "function" ? target.apply(this, arguments) : target, + i = d3_geo_greatArcInterpolate(a, b), + dt = precision / i.d, + t = 0, + coordinates = [a]; + while ((t += dt) < 1) coordinates.push(i(t)); + coordinates.push(b); + return { + type: "LineString", + coordinates: coordinates + }; + } + + // Length returned in radians; multiply by radius for distance. + greatArc.distance = function() { + var a = typeof source === "function" ? source.apply(this, arguments) : source, + b = typeof target === "function" ? target.apply(this, arguments) : target; + return d3_geo_greatArcInterpolate(a, b).d; + }; + + greatArc.source = function(x) { + if (!arguments.length) return source; + source = x; + return greatArc; + }; + + greatArc.target = function(x) { + if (!arguments.length) return target; + target = x; + return greatArc; + }; + + // Precision is specified in degrees. + greatArc.precision = function(x) { + if (!arguments.length) return precision / d3_geo_radians; + precision = x * d3_geo_radians; + return greatArc; + }; + + return greatArc; +}; + +function d3_geo_greatArcSource(d) { + return d.source; +} + +function d3_geo_greatArcTarget(d) { + return d.target; +} + +function d3_geo_greatArcInterpolate(a, b) { + var x0 = a[0] * d3_geo_radians, cx0 = Math.cos(x0), sx0 = Math.sin(x0), + y0 = a[1] * d3_geo_radians, cy0 = Math.cos(y0), sy0 = Math.sin(y0), + x1 = b[0] * d3_geo_radians, cx1 = Math.cos(x1), sx1 = Math.sin(x1), + y1 = b[1] * d3_geo_radians, cy1 = Math.cos(y1), sy1 = Math.sin(y1), + d = interpolate.d = Math.acos(Math.max(-1, Math.min(1, sy0 * sy1 + cy0 * cy1 * Math.cos(x1 - x0)))), + sd = Math.sin(d); + + // From http://williams.best.vwh.net/avform.htm#Intermediate + function interpolate(t) { + var A = Math.sin(d - (t *= d)) / sd, + B = Math.sin(t) / sd, + x = A * cy0 * cx0 + B * cy1 * cx1, + y = A * cy0 * sx0 + B * cy1 * sx1, + z = A * sy0 + B * sy1; + return [ + Math.atan2(y, x) / d3_geo_radians, + Math.atan2(z, Math.sqrt(x * x + y * y)) / d3_geo_radians + ]; + } + + return interpolate; +} +d3.geo.greatCircle = d3.geo.circle; +})(); |