Skip to content

Instantly share code, notes, and snippets.

@Fil
Last active Jul 29, 2017
Embed
What would you like to do?
Finding cracks [UNLISTED]
license: gpl-3.0
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
background: white;
}
.stroke {
fill: none;
stroke: #000;
stroke-width: 1.5px;
}
.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>
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.js"></script>
<script>
var width = 960,
height = 580;
var color = d3.scaleOrdinal(d3.schemeCategory20c);
var projection = d3.geoEquirectangular();
var path = d3.geoPath()
.projection(projection);
var svg = d3.select("body").append("svg")
.attr("width", width)
.attr("height", height);
function stitch(topology, arcs) {
var stitchedArcs = {},
fragmentByStart = {},
fragmentByEnd = {},
fragments = [],
emptyIndex = -1;
// Stitch empty arcs first, since they may be subsumed by other arcs.
arcs.forEach(function(i, j) {
var arc = topology.arcs[i < 0 ? ~i : i], t;
if (arc.length < 3 && !arc[1][0] && !arc[1][1]) {
t = arcs[++emptyIndex], arcs[emptyIndex] = i, arcs[j] = t;
}
});
arcs.forEach(function(i) {
var e = ends(i),
start = e[0],
end = e[1],
f, g;
if (f = fragmentByEnd[start]) {
delete fragmentByEnd[f.end];
f.push(i);
f.end = end;
if (g = fragmentByStart[end]) {
delete fragmentByStart[g.start];
var fg = g === f ? f : f.concat(g);
fragmentByStart[fg.start = f.start] = fragmentByEnd[fg.end = g.end] = fg;
} else {
fragmentByStart[f.start] = fragmentByEnd[f.end] = f;
}
} else if (f = fragmentByStart[end]) {
delete fragmentByStart[f.start];
f.unshift(i);
f.start = start;
if (g = fragmentByEnd[start]) {
delete fragmentByEnd[g.end];
var gf = g === f ? f : g.concat(f);
fragmentByStart[gf.start = g.start] = fragmentByEnd[gf.end = f.end] = gf;
} else {
fragmentByStart[f.start] = fragmentByEnd[f.end] = f;
}
} else {
f = [i];
fragmentByStart[f.start = start] = fragmentByEnd[f.end = end] = f;
}
});
function ends(i) {
var arc = topology.arcs[i < 0 ? ~i : i], p0 = arc[0], p1;
if (topology.transform) p1 = [0, 0], arc.forEach(function(dp) { p1[0] += dp[0], p1[1] += dp[1]; });
else p1 = arc[arc.length - 1];
return i < 0 ? [p1, p0] : [p0, p1];
}
function flush(fragmentByEnd, fragmentByStart) {
for (var k in fragmentByEnd) {
var f = fragmentByEnd[k];
delete fragmentByStart[f.start];
delete f.start;
delete f.end;
f.forEach(function(i) { stitchedArcs[i < 0 ? ~i : i] = 1; });
fragments.push(f);
}
}
flush(fragmentByEnd, fragmentByStart);
flush(fragmentByStart, fragmentByEnd);
arcs.forEach(function(i) { if (!stitchedArcs[i < 0 ? ~i : i]) fragments.push([i]); });
return fragments;
}
topojson.borders = function(topology) {
return meshArcs.apply(this, arguments);
}
function meshArcs(topology, object, filter, tag) {
var arcsl, tags, i, n;
if (arguments.length > 1) arcsl = extractArcs(topology, object, filter, tag), tags = arcsl[1], arcsl = arcsl[0];
else for (i = 0, arcs = new Array(n = topology.arcs.length); i < n; ++i) arcsl[i] = i, arcsl = [arcsl], tags = [0];
return {
type: "GeometryCollection",
geometries: arcsl.map(function(arcs, i) {
return {
type: "MultiLineString",
properties: { tag: tags[i] },
arcs: stitch(topology, arcs)
}
})
};
}
function extractArcs(topology, object, filter, tag) {
var tags = [],
arcs = [],
geomsByArc = [],
geom;
function extract0(i) {
var j = i < 0 ? ~i : i;
(geomsByArc[j] || (geomsByArc[j] = [])).push({i: i, g: geom});
}
function extract1(arcs) {
arcs.forEach(extract0);
}
function extract2(arcs) {
arcs.forEach(extract1);
}
function extract3(arcs) {
arcs.forEach(extract2);
}
function tagpush(i, tag) {
var t = tags.indexOf(tag);
if (t === -1) { tags.push(tag); t = arcs.length; arcs.push([]);}
arcs[t].push(i);
}
function geometry(o) {
switch (geom = o, o.type) {
case "GeometryCollection": o.geometries.forEach(geometry); break;
case "LineString": extract1(o.arcs); break;
case "MultiLineString": case "Polygon": extract2(o.arcs); break;
case "MultiPolygon": extract3(o.arcs); break;
}
}
geometry(object);
geomsByArc.forEach(filter == null
? function(geoms) { tagpush(geoms[0].i, tag(geoms[0].g)); }
: function(geoms) {
if (geoms[0].g.id == 728 || (geoms[1] && geoms[1].g.id == 728)) console.log(geoms[0].i, geoms[1] ? geoms[1].i : null)
if (filter(geoms[0].g, geoms[geoms.length - 1].g)) tagpush(geoms[0].i,tag(geoms[0].g, geoms[geoms.length - 1].g)); });
return [arcs, tags];
}
color(0); // fix coast line = color[0] = blue.
d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/world-110m.json", function(error, world) {
if (error) throw error;
var countries = topojson.feature(world, world.objects.countries).features,
neighbors = topojson.neighbors(world.objects.countries.geometries);
var borders = topojson.borders(
world,
world.objects.countries,
(a,b) => true /*a != b*/,
(a,b) => a==b ? 0 : d3.extent([a.id, b.id])
);
svg.selectAll('.border')
.data(topojson.feature(world, borders).features)
.enter()
.append('path')
.attr('d', path)
.attr('fill', 'none')
.attr('stroke', d => color(''+d.properties.tag))
.attr('stroke-width', d => d.properties.tag ? 0.5 : 2)
svg.append('path')
.datum({type:"Sphere"})
.attr('d', path)
.attr('class', 'stroke')
});
if (0)
d3.timer(e => {
projection.rotate([e/150])
svg.selectAll('path').attr('d', path)
}, 100)
</script>
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment