A v4 update to mbostock‘s block: Projection Transitions
I also tweaked the transition so that it’s constantly moving…
These projections are available in the geo.projection plugin.
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
background: #fcfcfa;
height: 500px;
position: relative;
width: 960px;
}
#projection-menu {
position: absolute;
right: 10px;
top: 10px;
}
.stroke {
fill: none;
stroke: #000;
stroke-width: 3px;
}
.fill {
fill: #fff;
}
.graticule {
fill: none;
stroke: #777;
stroke-width: .5px;
stroke-opacity: .5;
}
.land {
fill: #222;
}
.boundary {
fill: none;
stroke: #fff;
stroke-width: .5px;
}
</style>
<select id="projection-menu"></select>
<script src="//d3js.org/d3.v4.min.js"></script>
<script src="//d3js.org/d3-geo-projection.v1.min.js"></script>
<script src="//d3js.org/topojson.v2.min.js"></script>
<script>
var width = 960,
height = 500;
var options = [
{name: "Aitoff", projection: d3.geoAitoff()},
{name: "Albers", projection: d3.geoAlbers().scale(145).parallels([20, 50])},
{name: "August", projection: d3.geoAugust().scale(60)},
{name: "Baker", projection: d3.geoBaker().scale(100)},
{name: "Boggs", projection: d3.geoBoggs()},
{name: "Bonne", projection: d3.geoBonne().scale(120)},
{name: "Bromley", projection: d3.geoBromley()},
{name: "Collignon", projection: d3.geoCollignon().scale(93)},
{name: "Craster Parabolic", projection: d3.geoCraster()},
{name: "Eckert I", projection: d3.geoEckert1().scale(165)},
{name: "Eckert II", projection: d3.geoEckert2().scale(165)},
{name: "Eckert III", projection: d3.geoEckert3().scale(180)},
{name: "Eckert IV", projection: d3.geoEckert4().scale(180)},
{name: "Eckert V", projection: d3.geoEckert5().scale(170)},
{name: "Eckert VI", projection: d3.geoEckert6().scale(170)},
{name: "Eisenlohr", projection: d3.geoEisenlohr().scale(60)},
{name: "Equirectangular (Plate Carrée)", projection: d3.geoEquirectangular()},
{name: "Hammer", projection: d3.geoHammer().scale(165)},
{name: "Hill", projection: d3.geoHill()},
{name: "Goode Homolosine", projection: d3.geoHomolosine()},
{name: "Kavrayskiy VII", projection: d3.geoKavrayskiy7()},
{name: "Lambert cylindrical equal-area", projection: d3.geoCylindricalEqualArea()},
{name: "Lagrange", projection: d3.geoLagrange().scale(120)},
{name: "Larrivée", projection: d3.geoLarrivee().scale(95)},
{name: "Laskowski", projection: d3.geoLaskowski().scale(120)},
{name: "Loximuthal", projection: d3.geoLoximuthal()},
// {name: "Mercator", projection: d3.geoMercator().scale(490 / 2 / Math.PI)},
{name: "Miller", projection: d3.geoMiller().scale(100)},
{name: "McBryde–Thomas Flat-Polar Parabolic", projection: d3.geoMtFlatPolarParabolic()},
{name: "McBryde–Thomas Flat-Polar Quartic", projection: d3.geoMtFlatPolarQuartic()},
{name: "McBryde–Thomas Flat-Polar Sinusoidal", projection: d3.geoMtFlatPolarSinusoidal()},
{name: "Mollweide", projection: d3.geoMollweide().scale(165)},
{name: "Natural Earth", projection: d3.geoNaturalEarth()},
{name: "Nell–Hammer", projection: d3.geoNellHammer()},
{name: "Polyconic", projection: d3.geoPolyconic().scale(100)},
{name: "Robinson", projection: d3.geoRobinson()},
{name: "Sinusoidal", projection: d3.geoSinusoidal()},
{name: "Sinu-Mollweide", projection: d3.geoSinuMollweide()},
{name: "van der Grinten", projection: d3.geoVanDerGrinten().scale(75)},
{name: "van der Grinten IV", projection: d3.geoVanDerGrinten4().scale(120)},
{name: "Wagner IV", projection: d3.geoWagner4()},
{name: "Wagner VI", projection: d3.geoWagner6()},
{name: "Wagner VII", projection: d3.geoWagner7()},
{name: "Winkel Tripel", projection: d3.geoWinkel3()}
];
options.forEach(function(o) {
o.projection.rotate([0, 0]).center([0, 0]);
});
var //interval = setInterval(loop, 750),
i = 0,
n = options.length - 1;
var projection = options[i].projection;
var path = d3.geoPath(projection);
var graticule = d3.geoGraticule();
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
svg.append("defs").append("path")
.datum({type: "Sphere"})
.attr("id", "sphere")
.attr("d", path);
svg.append("use")
.attr("class", "stroke")
.attr("xlink:href", "#sphere");
svg.append("use")
.attr("class", "fill")
.attr("xlink:href", "#sphere");
svg.append("path")
.datum(graticule)
.attr("class", "graticule")
.attr("d", path);
d3.json("world-110m.json", function(error, world) {
if (error) throw error;
svg.insert("path", ".graticule")
.datum(topojson.feature(world, world.objects.land))
.attr("class", "land")
.attr("d", path);
});
var menu = d3.select("#projection-menu")
.on("change", change);
menu.selectAll("option")
.data(options)
.enter().append("option")
.text(function(d) { return d.name; });
update(options[0])
function loop() {
var j = Math.floor(Math.random() * n);
menu.property("selectedIndex", i = j + (j >= i));
update(options[i]);
}
function change() {
clearInterval(interval);
update(options[this.selectedIndex]);
}
function update(option) {
svg.selectAll("path").interrupt().transition()
.duration(1000).ease(d3.easeLinear)
.attrTween("d", projectionTween(projection, projection = option.projection))
d3.timeout(loop, 1000)
}
function projectionTween(projection0, projection1) {
return function(d) {
var t = 0;
var projection = d3.geoProjection(project)
.scale(1)
.translate([width / 2, height / 2]);
var path = d3.geoPath(projection);
function project(λ, φ) {
λ *= 180 / Math.PI, φ *= 180 / Math.PI;
var p0 = projection0([λ, φ]), p1 = projection1([λ, φ]);
return [(1 - t) * p0[0] + t * p1[0], (1 - t) * -p0[1] + t * -p1[1]];
}
return function(_) {
t = _;
return path(d);
};
};
}
</script>