在google地图叠加中使用d3绘制路径 [英] draw paths using d3 in google maps overlay
问题描述
我使用d3.js与谷歌地图，试图虚拟无线覆盖。基本思想是地图上的每个点将表示接入点，并且我将使用来自这些点的voronoi图作为覆盖的粗略近似等。
I'm using d3.js with google maps in a vain attempt to visualise wireless coverage. the basic idea is that each point on the map would represent an access point and i would use a voronoi diagram from these points as a crude approximation of coverage etc.
在此演示上，我有以下内容：
so based on this demo, i have the following:
<!DOCTYPE html>
<html>
<head>
<meta name="viewport" content="initial-scale=1.0, user-scalable=no"/>
<script type="text/javascript" src="http://maps.google.com/maps/api/js?sensor=true"></script>
<script type="text/javascript" src="http://mbostock.github.com/d3/d3.v2.min.js"></script>
<link rel="stylesheet" href="http://mbostock.github.com/d3/ex/colorbrewer.css">
<style type="text/css">
html, body, #map {
width: 100%;
height: 100%;
margin: 0;
padding: 0;
}
.stations {
position: absolute;
}
.stations, .stations svg {
position: absolute;
}
.stations border {
position: absolute;
stroke: black;
stroke-width: 2px;
}
.stations svg {
width: 60px;
height: 20px;
padding-right: 100px;
font: 10px sans-serif;
}
.stations circle {
fill: brown;
stroke: black;
stroke-width: 1.5px;
}
</style>
</head>
<body>
<div id="map"></div>
<script type="text/javascript">
// create map
var map = new google.maps.Map(d3.select("#map").node(), {
zoom: 8,
center: new google.maps.LatLng(37.76487, -122.41948),
mapTypeId: google.maps.MapTypeId.TERRAIN
});
var data = [
{ name: 'pt1', lng: -122.28, lat: 38.2 },
{ name: 'pt2', lng: -122.05, lat: 38.0 },
{ name: 'pt3', lng: -122.12, lat: 37.67 },
{ name: 'pt4', lng: -121.82, lat: 37.7 },
{ name: 'pt5', lng: -121.95, lat: 38.38 },
{ name: 'pt6', lng: -121.78, lat: 36.93 },
{ name: 'pt7', lng: -122.25, lat: 37.52 },
{ name: 'pt8', lng: -122.82, lat: 38.5 },
{ name: 'pt9', lng: -121.92, lat: 37.37 },
{ name: 'pt10', lng: -122.37, lat: 37.62 },
{ name: 'pt11', lng: -121.23, lat: 37.9 },
]
// Load the station data. When the data comes back, create an overlay.
var overlay = new google.maps.OverlayView();
// Add the container when the overlay is added to the map.
overlay.onAdd = function() {
var layer = d3.select(this.getPanes().overlayLayer).append("div")
.attr("height", "100%")
.attr("width", "100%")
.attr("class", "stations")
// Draw each marker as a separate SVG element.
// We could use a single SVG, but what size would it have?
overlay.draw = function() {
var projection = this.getProjection(),
padding = 10;
var marker = layer.selectAll("svg")
.data( data )
.each(transform) // update existing markers
.enter().append("svg:svg")
.each(transform)
.attr("class", "marker")
marker.append("svg:circle")
.attr("r", 4.5)
.attr("cx", padding )
.attr("cy", padding );
// add a label.
marker.append("svg:text")
.attr("x", padding + 7)
.attr("y", padding)
.attr("dy", ".31em")
.text( function(d) {
return d.name; }
);
var v = d3.geom.voronoi( translate(data) );
// console.log( v )
var edges = layer.selectAll("path")
.data( v )
.enter().append("svg:svg")
.attr( "class", "border" )
.append("svg:path")
.attr( "d", function(d){
var e = transform_path(d)
var p = 'M' + e.join('L') + 'Z'
console.log( 'PATH: ' + p)
return p
})
function translate(data) {
var d = []
for( var i=0; i<data.length; i++){
var c = [ data[i].lat, data[i].lng ]
d.push( c )
}
return d
}
function _projection( lat, lng ) {
e = new google.maps.LatLng( lat, lng );
e = projection.fromLatLngToDivPixel(e);
return [ e.x - padding, e.y - padding]
// return [ e.x, e.y ]
}
function transform(d) {
e = _projection( d.lat, d.lng )
console.log("marker " + d.lat +', ' + d.lng + " -> left: " + e[0] +", top: " + e[1] )
return d3.select(this)
.style("left", e[0] + "px")
.style("top", e[1] + "px");
}
function transform_path(data) {
var d = []
console.log(data)
for( var i=0; i<data.length; i++) {
var c = _projection( data[i][0], data[i][2] )
console.log( ' path point: ' + JSON.stringify(data[i]) + ' -> left: ' + c[0] + ", top: " + c[1])
d.push( c )
}
// console.log(d)
return d
}
};
};
// Bind our overlay to the map…
overlay.setMap(map);
</script>
</body>
</html>
但是，我不能得到任何路径元素。可以任何一个帮助？我有上面的代码在 jsfiddle 。干杯！
However, i can not get any of the path elements showing up. can any one help? i have the above code up on jsfiddle. cheers!
推荐答案
在这里你可以看到路径显示。你的问题与D3无关，但是CSS样式不好：width设置为0px，圆圈的样式给予路径等。
Here you can see the paths showing up. Your problem was not related to D3, but to bad CSS styling : width were set to 0px, styles for the circles were given to the paths, etc.
我也注意到设计缺陷：你的点不应该通过绝对定位CSS，而是通过SVG定位（让D3做你的伎俩）。我的建议是清楚地分离叠加层和Google地图。棘手的部分是确保它们一起移动（缩放和左右上下）
I also noticed design flaws : your dots should not be positioned with CSS through absolute positioning, but rather through SVG positioning (let D3 do the trick for you). My advice would be to separate clearly the overlay and the Google map. The tricky part would be to make sure that they move together (zooms and left-right up-down)
good luck
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