Difference between revisions of "Team:SJTU-BioX-Shanghai/HP test page"

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li{margin-bottom:0;}
 
li{margin-bottom:0;}
 
</style>
 
</style>
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 +
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 +
  
 
<!DOCTYPE html>
 
<!DOCTYPE html>
 
<meta charset="utf-8">
 
<meta charset="utf-8">
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<title>Geographic Bounding Boxes</title>
 
 
<style>
 
<style>
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@import url(../maps.css?85b2875);
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#map svg {
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h1 {
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   cursor: move;
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   position: absolute;
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}
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   top: 500px;
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path {
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   font-family: "Helvetica Neue", Helvetica, Arial, sans-serif;
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   fill: none;
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   font-size: 18px;
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   stroke: #000;
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   text-align: center;
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}
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   width: 960px;
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.background {
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  stroke: none;
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−
  fill: #eef;
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}
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.land {
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  stroke-width: .75px;
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−
  pointer-events: all;
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}
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.graticule {
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  stroke: #333;
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   stroke-width: .25px;
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}
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.bounds {
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  fill: #f00;
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   fill-opacity: .25;
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   stroke: #000;
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  stroke-width: 1px;
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  pointer-events: none;
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}
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.country:hover .bounds {
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  stroke-width: 2px;
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}
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.country:hover .land {
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  stroke-width: 1px;
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}
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.outline {
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  stroke: #000;
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  stroke-width: 1.5px;
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  fill: none;
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}
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.antimeridian {
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  stroke-dasharray: 5 5;
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}
 
}
  
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.example path.Polygon {
 
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  fill: url(#hatch);
 
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}
 
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.example text {
 
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  font-size: 11px;
 
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  font-family: sans-serif;
 
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}
 
 
</style>
 
</style>
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<h1></h1>
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<script src="//d3js.org/d3.v3.min.js"></script>
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<script src="//d3js.org/queue.v1.min.js"></script>
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<script src="//d3js.org/topojson.v1.min.js"></script>
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<script>
  
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<p class="breadcrumbs"><a href="http://www.jasondavies.com/">Jason Davies</a> → <a href="../">Maps</a>
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var width = 960,
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    height = 960;
  
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<h1>Geographic Bounding Boxes</h1>
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var projection = d3.geo.orthographic()
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<div id="map"></div>
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    .translate([width / 2, height / 2])
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    .scale(width / 2 - 20)
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    .clipAngle(90)
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    .precision(0.6);
  
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<div class="wrapper">
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var canvas = d3.select("body").append("canvas")
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  <p class="caption">A geographic bounding box for each country (including semi-independent regions) from Natural Earth’s <a href="http://www.naturalearthdata.com/downloads/110m-cultural-vectors/110m-admin-0-countries/">1:110m Cultural Vectors</a>.
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    .attr("width", width)
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    .attr("height", height);
  
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  <p>A <a href="http://en.wikipedia.org/wiki/Minimum_bounding_box">minimum bounding box</a> in <i>geographic coordinates</i> is an area defined by minimum and maximum longitudes and latitudes.
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var c = canvas.node().getContext("2d");
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  <p>Computing bounding boxes in 2D is simple: track the minimum and maximum x- and y-coordinates point by point.
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  Assuming line segments are straight for both polylines and polygons, nothing else needs to be done.
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  <p>Why doesn’t this work for a sphere?
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  <h2>The Antimeridian</h2>
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var path = d3.geo.path()
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  <p>Imagine a set of points clustered around the antimeridian at 180°E.
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    .projection(projection)
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  A 2D algorithm will find a bounding box with longitudes extending all the way from around -180° to around +180°, even if the true <i>minimum</i> bounding box has a much smaller width.
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    .context(c);
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  <p>A better approach is to compute the true minimum-width bounding box, even if it crosses the antimeridian.
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  <div class="example"></div>
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  <h2>Line Segments</h2>
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var title = d3.select("h1");
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  <p>D3 treats line segments as great-circle arcs: two successive points define the minor arc of the great circle going through those points.
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  <p>Here we need to be even more careful than for points, since it matters whether or not the line crosses the antimeridian.
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  <div class="example"></div>
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  <p>In addition, intermediate points between the segment endpoints may have latitudes extending beyond the maximum or minimum endpoint latitude.
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queue()
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  <div class="example"></div>
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    .defer(d3.json, "/mbostock/raw/4090846/world-110m.json")
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    .defer(d3.tsv, "/mbostock/raw/4090846/world-country-names.tsv")
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    .await(ready);
  
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  <h2>Polygons</h2>
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function ready(error, world, names) {
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  <p>A polygon may contain any number of holes, and the location of its interior depends on the winding order of its vertices.
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   if (error) throw error;
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   <p>In D3, if a polygon’s vertices wind around a point in a counter-clockwise direction, this means the point is outside the polygon.
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  Otherwise, it is inside <span id="inside"></span>.
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  <div class="example"></div>
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   <p>If a polygons vertices wind around either pole, this means the longitudes have maximum extent from 180°W to +180°E.
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   var globe = {type: "Sphere"},
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  <div class="example"></div>
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      land = topojson.feature(world, world.objects.land),
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      countries = topojson.feature(world, world.objects.countries).features,
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      borders = topojson.mesh(world, world.objects.countries, function(a, b) { return a !== b; }),
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      i = -1,
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      n = countries.length;
  
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   <p>Lastly, a polygon may contain either pole, even if its vertices do not extend to the pole, in which case the latitude extent is extended to the pole.
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   countries = countries.filter(function(d) {
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   <div class="example"></div>
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    return names.some(function(n) {
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      if (d.id == n.id) return d.name = n.name;
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    });
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  }).sort(function(a, b) {
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    return a.name.localeCompare(b.name);
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   });
  
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   <h2>Further Reading</h2>
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   (function transition() {
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  <p>The described behaviour is supported by <code>d3.geo.bounds</code> as of <a href="http://d3js.org">D3</a> version <a href="https://github.com/mbostock/d3/releases/tag/v3.1.7">3.1.7</a>.
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    d3.transition()
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</div>
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        .duration(1250)
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        .each("start", function() {
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          title.text(countries[i = (i + 1) % n].name);
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        })
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        .tween("rotate", function() {
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          var p = d3.geo.centroid(countries[i]),
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              r = d3.interpolate(projection.rotate(), [-p[0], -p[1]]);
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          return function(t) {
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            projection.rotate(r(t));
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            c.clearRect(0, 0, width, height);
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            c.fillStyle = "#ccc", c.beginPath(), path(land), c.fill();
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            c.fillStyle = "#f00", c.beginPath(), path(countries[i]), c.fill();
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            c.strokeStyle = "#fff", c.lineWidth = .5, c.beginPath(), path(borders), c.stroke();
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            c.strokeStyle = "#000", c.lineWidth = 2, c.beginPath(), path(globe), c.stroke();
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          };
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        })
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      .transition()
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        .each("end", transition);
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  })();
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}
  
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<script src="../../d3.min.js?94db87"></script>
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d3.select(self.frameElement).style("height", height + "px");
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<script src="../topojson.min.js?1.1.1"></script>
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−
<script src="app.min.js"></script>
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 +
</script>
  
  
 
</html>
 
</html>

Revision as of 22:00, 13 August 2018