Create a gist now

Instantly share code, notes, and snippets.

Zoom/pan map example: integrates d3.geo with d3.behavior with the aim of producing a map that can be panned and zoomed.
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html lang="en">
<head>
<!--
Zoom/pan map example: integrates d3.geo with d3.behavior with the aim of
producing a map that can be panned and zoomed.
Iain Dillingham, http://dillingham.me.uk/
-->
<title>Zoom/pan map example</title>
<script type="text/javascript" src="https://raw.github.com/mbostock/d3/master/d3.min.js"></script>
<script type="text/javascript" src="https://raw.github.com/mbostock/d3/master/d3.geo.min.js"></script>
<style type="text/css">
#uk {
fill: #E5F5F9;
stroke: #2CA25F;
stroke-width: 0.5;
}
#axes {
stroke: #BDBDBD;
stroke-width: 0.5;
}
</style>
</head>
<body>
<div id="vis"></div>
<script type="text/javascript">
var w = 960;
var h = 500;
var proj = d3.geo.mercator();
var path = d3.geo.path().projection(proj);
var t = proj.translate(); // the projection's default translation
var s = proj.scale() // the projection's default scale
var map = d3.select("#vis").append("svg:svg")
.attr("width", w)
.attr("height", h)
.call(d3.behavior.zoom().on("zoom", redraw));
var axes = map.append("svg:g").attr("id", "axes");
var xAxis = axes.append("svg:line")
.attr("x1", t[0])
.attr("y1", 0)
.attr("x2", t[0])
.attr("y2", h);
var yAxis = axes.append("svg:line")
.attr("x1", 0)
.attr("y1", t[1])
.attr("x2", w)
.attr("y2", t[1]);
var uk = map.append("svg:g").attr("id", "uk");
d3.json("uk.json", function (json) {
uk.selectAll("path")
.data(json.features)
.enter().append("svg:path")
.attr("d", path);
});
function redraw() {
// d3.event.translate (an array) stores the current translation from the parent SVG element
// t (an array) stores the projection's default translation
// we add the x and y vales in each array to determine the projection's new translation
var tx = t[0] * d3.event.scale + d3.event.translate[0];
var ty = t[1] * d3.event.scale + d3.event.translate[1];
proj.translate([tx, ty]);
// now we determine the projection's new scale
proj.scale(s * d3.event.scale);
// redraw the map
uk.selectAll("path").attr("d", path);
// redraw the x axis
xAxis.attr("x1", tx).attr("x2", tx);
// redraw the y axis
yAxis.attr("y1", ty).attr("y2", ty);
}
</script>
</body>
</html>
Sorry, something went wrong. Reload?
Sorry, we cannot display this file.
Sorry, this file is invalid so it cannot be displayed.
Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment