I have a map that is zooming back and forth between a couple of locations. However, my map coordinates are off. It appears the map is centered at [0,0] by default. I changed projection.center to a new point, but this caused some chaos-- (the map started zooming to other continents...)
Here is a plunker with the map, with the 0,0 center (mouse over and you'll see the coordinates at the bottom).
I also tried setting projection.center within the zoomTo function, but that caused another problem. I feel like this should be a quick edit, but I've spent a lot of time pulling my hair out on this.
Any ideas on what needs to change?
Many thanks.
Code also below:
<!DOCTYPE html>
<meta charset="utf-8">
<style>
body {
margin: 0;
}
#container {
position: relative;
overflow: hidden;
}
#map{
width:100%;
height:100%;
}
.layer {
position: absolute;
}
.tile {
pointer-events: none;
position: absolute;
width: 256px;
height: 256px;
}
.info {
position: absolute;
bottom: 0px;
left: 0px;
padding: 20px;
background: #000;
color: #fff;
width: 100%;
z-index: 1000;
}
</style>
<body>
<script src="http://d3js.org/d3.v3.min.js"></script>
<script src="http://d3js.org/d3.geo.tile.v0.min.js"></script>
<div id="canvas">
<div id="container">
<div id="map">
<div class="layer"></div>
</div>
</div>
</div>
<script>
var width = Math.max(960, window.innerWidth),
height = Math.max(500, window.innerHeight),
prefix = prefixMatch(["webkit", "ms", "Moz", "O"]);
var tile = d3.geo.tile()
.size([width, height]);
var sf = [-122.417, 37.775],
belowsf = [-122.510962, 37.580284];
var projection = d3.geo.mercator()
.scale((1 << 18) / 2 / Math.PI)
.translate([-width / 2, -height / 2]); // just temporary
var map = d3.select("#map");
var layer = d3.select(".layer");
var zoom = d3.behavior.zoom().on("zoom", zoomed);
var canvas = d3.select("#canvas")
.style("width", width + "px")
.style("height", height + "px");
var container = d3.select("#container")
.style("width", width + "px")
.style("height", height + "px")
.on("mousemove", mousemoved);
canvas
.call(zoomTo(sf).event)
.transition()
.duration(10000)
.each(jump);
var info = map.append("div")
.attr("class", "info");
function zoomTo(place) {
return zoom
.scale(projection.scale() * 2 * Math.PI)
.translate(projection(place).map(function(x) { return -x; }));
}
function jump() {
var t = d3.select(this);
(function repeat() {
t = t.transition()
.call(zoomTo(belowsf).event)
.transition()
.call(zoomTo(sf).event)
.each("end", repeat);
})();
}
function mousemoved() {
info.text(formatLocation(projection.invert(d3.mouse(this)), zoom.scale()));
}
function zoomed() {
var tiles = tile
.scale(zoom.scale())
.translate(zoom.translate())
();
var image = layer
.style(prefix + "transform", matrix3d(tiles.scale, tiles.translate))
.selectAll(".tile")
.data(tiles, function(d) { return d; });
image.exit()
.remove();
image.enter().append("img")
.attr("class", "tile")
.attr("src", function(d) { return "http://" + ["a", "b", "c"][Math.random() * 3 | 0] + ".basemaps.cartocdn.com/light_all/" + d[2] + "/" + d[0] + "/" + d[1] + ".png"; })
.style("left", function(d) { return (d[0] << 8) + "px"; })
.style("top", function(d) { return (d[1] << 8) + "px"; });
}
function matrix3d(scale, translate) {
var k = scale / 256, r = scale % 1 ? Number : Math.round;
return "matrix3d(" + [k, 0, 0, 0, 0, k, 0, 0, 0, 0, k, 0, r(translate[0] * scale), r(translate[1] * scale), 0, 1 ] + ")";
}
function prefixMatch(p) {
var i = -1, n = p.length, s = document.body.style;
while (++i < n) if (p[i] + "Transform" in s) return "-" + p[i].toLowerCase() + "-";
return "";
}
function formatLocation(p, k) {
var format = d3.format("." + Math.floor(Math.log(k) / 2 - 2) + "f");
return (p[1] < 0 ? format(-p[1]) + "°S" : format(p[1]) + "°N") + " "
+ (p[0] < 0 ? format(-p[0]) + "°W" : format(p[0]) + "°E");
}
</script>
</body>
</html>
Screenshot, showing incorrect coordinates:
