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jasondaviesjasondavies
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d3.geo.area: return positive areas.
1 parent 7860b0d commit e0c91c1

4 files changed

Lines changed: 30 additions & 6 deletions

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‎d3.js‎

Lines changed: 1 addition & 1 deletion
Original file line numberDiff line numberDiff line change
@@ -5519,7 +5519,7 @@
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λ0 = λ, φ0 = φ;
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cosφ0 = cosφ, sinφ0 = sinφ;
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}
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return area > 2 * π && area <= 4 * π ? 4 * π - area : area <= -2 * π && area > -4 * π ? area + 4 * π : area;
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return Math.abs(area < -ε ? 4 * π + area : area);
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}
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var d3_geo_azimuthalEqualArea = d3_geo_azimuthal(function(cosλcosφ) {
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return Math.sqrt(2 / (1 + cosλcosφ));

‎d3.min.js‎

Lines changed: 1 addition & 1 deletion
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‎src/geo/area.js‎

Lines changed: 2 additions & 4 deletions
Original file line numberDiff line numberDiff line change
@@ -13,7 +13,7 @@ var d3_geo_areaType = d3_geo_type({
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Feature: function(feature) { return d3_geo_areaType.geometry(feature.geometry); },
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FeatureCollection: function(collection) { return d3.sum(collection.features, d3_geo_areaType.Feature); },
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GeometryCollection: function(collection) { return d3.sum(collection.geometries, d3_geo_areaType.geometry); },
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geometry: function(geometry) { return d3_geo_areaType[geometry.type](geometry); } // TODO add 3rd argument to d3.sum?
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geometry: function(geometry) { return d3_geo_areaType[geometry.type](geometry); }
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});
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function d3_geo_areaPolygon(polygon) {
@@ -58,7 +58,5 @@ function d3_geo_areaRing(ring) {
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λ0 = λ, φ0 = φ;
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cosφ0 = cosφ, sinφ0 = sinφ;
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}
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return area > 2 * π && area <= 4 * π ? 4 * π - area
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: area <= -2 * π && area > -4 * π ? area + 4 * π
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: area;
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return Math.abs(area < -ε ? 4 * π + area : area);
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}

‎test/geo/area-test.js‎

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Original file line numberDiff line numberDiff line change
@@ -55,6 +55,32 @@ suite.addBatch({
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"semilune": function(area) {
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assert.inDelta(area(d3.geo.graticule().extent([[0, 0], [90, 90]]).outline()), π / 2, 1e-5);
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}
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},
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"circles": {
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"hemisphere": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(90)()), 2 * π, 1e-5);
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},
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"45°": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(45).precision(.1)()), π * (2 - Math.SQRT2), 1e-5);
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},
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"45° North": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(45).precision(.1).origin([0, 90])()), π * (2 - Math.SQRT2), 1e-5);
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},
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"45° South": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(45).precision(.1).origin([0, -90])()), π * (2 - Math.SQRT2), 1e-5);
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},
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"135°": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(135).precision(.1)()), π * (2 + Math.SQRT2), 1e-5);
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},
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"135° North": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(135).precision(.1).origin([0, 90])()), π * (2 + Math.SQRT2), 1e-5);
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},
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"135° South": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(135).precision(.1).origin([0, -90])()), π * (2 + Math.SQRT2), 1e-5);
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},
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"tiny": function(area) {
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assert.inDelta(area(d3.geo.circle().angle(1e-6)()), 0, 1e-6);
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}
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}
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},
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"MultiPolygon": {

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