Instead of drawing straight lines from a certain set of coordinates to another, d3.geo generates great arcs. These paths are the shortest distance between two points on a sphere.
| <!DOCTYPE html> | |
| <meta charset="utf-8" /> | |
| <body> | |
| <script src="//d3js.org/d3.v3.min.js"></script> | |
| <script src="//d3js.org/topojson.v1.min.js"></script> | |
| <script src="//d3js.org/d3.geo.projection.v0.min.js"></script> | |
| <script src="//cdn.rawgit.com/mourner/rbush/master/rbush.js"></script> | |
| <script src="//cdn.rawgit.com/newsappsio/spam/master/spam.min.js"></script> | |
| <script type='text/javascript'> | |
| var width = 960, | |
| height = 960 | |
| var graticule = d3.geo.graticule() | |
| var route = { | |
| type: "LineString", | |
| coordinates: [ | |
| [-77.05, 38.91], [116.35, 39.91], | |
| [-39.927962, -5.058878], [46.587640, -18.909864] | |
| ] | |
| } | |
| d3.json("world.json", function(error, d) { | |
| topojson.presimplify(d) | |
| var map = new StaticCanvasMap({ | |
| element: "body", | |
| width: width, | |
| height: height, | |
| projection: d3.geo.azimuthalEquidistant() | |
| .scale(160) | |
| .translate([width / 2, height / 2]) | |
| .clipAngle(180 - 4e-3) | |
| .precision(.1), | |
| data: [{ | |
| features: topojson.feature(d, d.objects["countries"]), | |
| static: { | |
| prepaint: function(parameters) { | |
| parameters.context.beginPath() | |
| parameters.path(graticule()) | |
| parameters.context.lineWidth = 0.2 | |
| parameters.context.strokeStyle = 'rgba(30,30,30, 0.5)' | |
| parameters.context.stroke() | |
| }, | |
| paintfeature: function(parameters, d) { | |
| parameters.context.lineWidth = 1.5 | |
| parameters.context.strokeStyle = "rgb(255,255,255)" | |
| parameters.context.stroke() | |
| parameters.context.fillStyle = "rgb(225, 220, 220)"; | |
| parameters.context.fill() | |
| }, | |
| postpaint: function(parameters) { | |
| parameters.context.beginPath() | |
| parameters.path(route) | |
| parameters.context.strokeStyle = "rgb(209, 25, 25)" | |
| parameters.context.stroke() | |
| } | |
| } | |
| } | |
| ] | |
| }) | |
| map.init() | |
| }) | |
| </script> |
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