mbostock/.block

## .block
license: gpl-3.0
redirect: https://observablehq.com/@d3/tissots-indicatrix

## README.md

      
    Raw
  

              README.md
            
          
    False Tissot's Indicatrix approximated with small circles, based on work by Tom Carden. A true Tissot’s Indicatrix has now been implemented by Jason Davies.

  
## index.html
<!DOCTYPE html>
<meta charset="utf-8">
<style>

body {
  background: #fcfcfa;
}

.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;
}

.tissot {
  fill: orange;
  fill-opacity: .4;
  stroke: brown;
}

</style>
<body>
<script src="//d3js.org/d3.v3.min.js"></script>
<script src="//d3js.org/topojson.v1.min.js"></script>
<script>

var width = 960,
    height = 960;

var projection = d3.geo.orthographic()
    .scale(475)
    .translate([width / 2, height / 2])
    .clipAngle(90)
    .precision(.1);

var path = d3.geo.path()
    .projection(projection);

var graticule = d3.geo.graticule();

var xz = d3.range(-180, 181, 30),
    yz = d3.range(-60, 61, 30),
    circle = d3.geo.circle().angle(7).origin(function(x, y) { return [x, y]; }),
    circles = d3.merge(xz.map(function(x) { return yz.map(function(y) { return circle(x, y); }); }));

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);

svg.append("path")
    .datum({type: "GeometryCollection", geometries: circles})
    .attr("class", "tissot")
    .attr("d", path);

d3.json("/mbostock/raw/4090846/world-50m.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);

  svg.insert("path", ".graticule")
      .datum(topojson.mesh(world, world.objects.countries, function(a, b) { return a !== b; }))
      .attr("class", "boundary")
      .attr("d", path);
});

d3.select(self.frameElement).style("height", height + "px");

</script>

## thumbnail.png

      
    Raw
  

              thumbnail.png
	license: gpl-3.0
	redirect: https://observablehq.com/@d3/tissots-indicatrix
	<!DOCTYPE html>
	<meta charset="utf-8">
	<style>

	body {
	background: #fcfcfa;
	}

	.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;
	}

	.tissot {
	fill: orange;
	fill-opacity: .4;
	stroke: brown;
	}

	</style>
	<body>
	<script src="//d3js.org/d3.v3.min.js"></script>
	<script src="//d3js.org/topojson.v1.min.js"></script>
	<script>

	var width = 960,
	height = 960;

	var projection = d3.geo.orthographic()
	.scale(475)
	.translate([width / 2, height / 2])
	.clipAngle(90)
	.precision(.1);

	var path = d3.geo.path()
	.projection(projection);

	var graticule = d3.geo.graticule();

	var xz = d3.range(-180, 181, 30),
	yz = d3.range(-60, 61, 30),
	circle = d3.geo.circle().angle(7).origin(function(x, y) { return [x, y]; }),
	circles = d3.merge(xz.map(function(x) { return yz.map(function(y) { return circle(x, y); }); }));

	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);

	svg.append("path")
	.datum({type: "GeometryCollection", geometries: circles})
	.attr("class", "tissot")
	.attr("d", path);

	d3.json("/mbostock/raw/4090846/world-50m.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);

	svg.insert("path", ".graticule")
	.datum(topojson.mesh(world, world.objects.countries, function(a, b) { return a !== b; }))
	.attr("class", "boundary")
	.attr("d", path);
	});

	d3.select(self.frameElement).style("height", height + "px");

	</script>