block by hugolpz 1c34e14d8b7dd457f802

Printing map.svg file via D3js, Nodejs, Jsdom

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D3 map client & server side

Minimal demo on how to create maps both :

  1. client side via d3js, topojson, & queue.js
  2. server side via exact same ressources + nodejs.

JS

Data

The topojson data is loaded via http request and so should be stored online. Client side accept relative url, serverside requires absolute url (http://x.yz/a/file.json).

Client side

Open ./index.html in web browser. Viz based on ./script.js D3js codes.

Server side via Nodejs

Based on the exact same ./script.js. Thanks to npm jsdom, we create on serverside a virtual browser, the svg dataviz, to grab this svg element and print it out.

Dependencies:

 npm install   # install jsdom locally

In terminal, pass variables and run the nodejs code: 

WIDTH=800 \
    URL=http://bl.ocks.org/hugolpz/raw/1c34e14d8b7dd457f802/administrative.topo.json \
    node mapIt.node.js

It creates the standalone map.svg file similar to the client side map.

script.js

var mapIt = function(width, url){
    console.log("mapIt(): start");
	var height = width/960*500;
    var svg = d3.select('body').append('svg')
        .attr('width', width)
        .attr('height', height)
		.attr("xmlns","http://www.w3.org/2000/svg");
	
	var projection = d3.geo.equirectangular()
		  .scale(1)
		  .translate([0, 0]);
    var path = d3.geo.path()
        .projection(projection);
	
	queue()
		.defer(d3.json,url)
		.await(mapping);
	
    function mapping(error, json) {
		if (error) return console.warn(error);
		var admin_0 = topojson.feature(json, json.objects.admin_0);

		// Compute the bounds of a feature of interest, then derive scale & translate.
		var b = path.bounds(admin_0),
			s = .95 / Math.max((b[1][0] - b[0][0]) / width, (b[1][1] - b[0][1]) / height),
			t = [(width - s * (b[1][0] + b[0][0])) / 2, (height - s * (b[1][1] + b[0][1])) / 2];
		// Update the projection to use computed scale & translate.
		projection
			.scale(s)
			.translate(t);

		svg.append("g")
			.attr("style","fill:#333;stroke-width:1px;stroke-color:white;")
		.selectAll("path")
			.data(admin_0.features)
		.enter().append("path")
			.attr('class', 'L0')
			.attr('d', path);
	};
};

index.html

<!DOCTYPE html>
<meta http-equiv="content-type" content="text/html; charset=utf-8">
<style>
* { transition: .4s;}
.L0:hover { fill: #5d6a7a;}
svg { border: 1px solid #000;}
</style>
<body>
<script src="./d3.v3.min.js"></script>
<script src="./topojson.v1.min.js"></script>
<script src="./queue.v1.min.js"></script>
<script src="./script.js"></script>
<script>
mapIt(800,"./administrative.topo.json");
</script>
</body>
</html>

mapIt.node.js

// Run me with and pass me variables: 
// $ WIDTH=800 ITEM="world-1e3" node mapIt.node.js
/* ***************************************************************** */
//Nodejs code:
var jsdom = require('jsdom');  		// npm install jsdom
var fs    = require('fs'); 			// natively in nodejs.

jsdom.env(
  "<html><body></body></html>",     // CREATE DOM HOOK
  [ './d3.v3.min.js', 				// load assets into window environment (!)
  './topojson.v1.min.js', 
  './queue.v1.min.js', 
  './script.js' ],

  function (err, window) {
    /* ***************************************************************** */
    /* Check availability of loaded assets in window scope. ************ */
    console.log(typeof window.mapIt);       // expect: 'function',  because exist in script.js !
    console.log(typeof window.doesntExist); // expect: 'undefined', because doesn't exist anywhere.
    // if all as expected, should work !

    /* ***************************************************************** */
    /* COLLECT ENV.VARIABLES ******************************************* */
    var width = process.env.WIDTH,
        url= process.env.URL;

    /* ***************************************************************** */
    /* D3js FUNCTION *************************************************** */
    window.mapIt(width,url);		// nb: "window." (!) to use assets within window environment
    // Half of window.mapIt() works. See script.js & output map.svg. 

    /* ***************************************************************** */
    /* SVG PRINT ******************************************************* */
    // better svg header:
    var svgheader = '<?xml version="1.0" encoding="utf-8"?>\n'
    +'<!DOCTYPE svg PUBLIC "-//W3C//DTD SVG 1.1//EN" "http://www.w3.org/Graphics/SVG/1.1/DTD/svg11.dtd">\n';
    // printing + timer, to be sure all is ready when printing file:
    setTimeout(
      function(){ fs.writeFileSync('map.svg', svgheader + window.d3.select("body").html()); },
      7000
    );

 }
);

package.json

{
  "name": "D3js_map",
  "version": "0.0.1",
  "description": "Nodejs + D3js minimal mapping system",
  "main": "nothing here",
  "dependencies": {
      "jsdom":"~1.0.3"
  },
  "author": "Hugo lopez and Arun Ganesh",
  "license": "BSD"
}

queue.v1.min.js

!function(){function n(n){function e(){for(;i=a<c.length&&n>p;){var u=a++,e=c[u],o=t.call(e,1);o.push(l(u)),++p,e[0].apply(null,o)}}function l(n){return function(u,t){--p,null==s&&(null!=u?(s=u,a=d=0/0,o()):(c[n]=t,--d?i||e():o()))}}function o(){null!=s?m(s):f?m(s,c):m.apply(null,[s].concat(c))}var r,i,f,c=[],a=0,p=0,d=0,s=null,m=u;return n||(n=1/0),r={defer:function(){return s||(c.push(arguments),++d,e()),r},await:function(n){return m=n,f=!1,d||o(),r},awaitAll:function(n){return m=n,f=!0,d||o(),r}}}function u(){}var t=[].slice;n.version="1.0.7","function"==typeof define&&define.amd?define(function(){return n}):"object"==typeof module&&module.exports?module.exports=n:this.queue=n}();

topojson.v1.min.js

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t=0>n?~n:n;(s[t]||(s[t]=[])).push({i:n,g:a})}function i(n){n.forEach(o)}function u(n){n.forEach(i)}function f(n){"GeometryCollection"===n.type?n.geometries.forEach(f):n.type in l&&(a=n,l[n.type](n.arcs))}var c=[];if(arguments.length>1){var a,s=[],l={LineString:i,MultiLineString:u,Polygon:u,MultiPolygon:function(n){n.forEach(u)}};f(r),s.forEach(arguments.length<3?function(n){c.push(n[0].i)}:function(n){e(n[0].g,n[n.length-1].g)&&c.push(n[0].i)})}else for(var h=0,p=n.arcs.length;p>h;++h)c.push(h);return{type:"MultiLineString",arcs:t(n,c)}}function e(r,e){function o(n){n.forEach(function(t){t.forEach(function(t){(f[t=0>t?~t:t]||(f[t]=[])).push(n)})}),c.push(n)}function i(n){return l(u(r,{type:"Polygon",arcs:[n]}).coordinates[0])>0}var f={},c=[],a=[];return e.forEach(function(n){"Polygon"===n.type?o(n.arcs):"MultiPolygon"===n.type&&n.arcs.forEach(o)}),c.forEach(function(n){if(!n._){var 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