解析geojson文件后，为什么在浏览器中看不到地图？

Question

I have the huge geojson showing all the districts of Dubai. Here is a sample:

{
    "type":"FeatureCollection",
    "totalFeatures":224,
    "features":[
        {
            "type":"Feature",
            "id":"Community.1",
            "geometry":{
                "type":"MultiPolygon",
                "coordinates":[
                    [
                        [

                            [
                                55.16945847438926,
                                25.03005371689898
                            ],
                            [
                                55.168575711653915,
                                25.03074785219016
                            ],
                            [
                                55.169258376227525,
                                25.03150691074316
                            ],
                            [
                                55.169931129543535,
                                25.032274981961805
                            ],

                        ]
                    ]
                ]
            },
            "geometry_name":"the_geom",
            "properties":{
                "COMM_CODE":684,
                "NAME_AR":"البرشاء الجنوب الخامسة",
                "NAME_EN":"AL BARSHA SOUTH FIFTH",
                "AREA_ID":442,
                "SHAPE_AREA":2951425.95614,
                "SHAPE_LEN":10871.405155
            }
        },
        {
            "type":"Feature",
            "id":"Community.2",
            "geometry":{
                "type":"MultiPolygon",
                "coordinates":[
                    [
                        [
                            [
                                55.34592943407097,
                                25.16925511754935
                            ],

                            [
                                55.34604885385063,
                                25.17297434345408
                            ],
                            [
                                55.34600905862783,
                                25.171854965446766
                            ],
                            [
                                55.345979182892805,
                                25.170726559094064
                            ],
                            [
                                55.34592943407097,
                                25.16925511754935
                            ]
                        ]
                    ]
                ]
            }

I have a very simple code in d3, that parses the geojson and displays it in the browser. However I cannot see the results.

Here is my code:

 d3.json("dld.json", createMap);

    function createMap(countries) {
        var aProjection = d3.geo.mercator();
        var geoPath = d3.geo.path().projection(aProjection);
        d3.select("svg").selectAll("path").data(countries.features)
            .enter()
            .append("path")
            .attr("d", geoPath)
            .attr("class", "countries")
    }

There is no error displayed in the console. If someone could please point to me where I've mistaken, I would be the most thankful :)

Answer 1

The issue is, that you haven't yet set your bounding box you want to view in the map. For this you can extend your projection like this:

var aProjection = d3.geo.mercator().scale(1000).translate([-1000, 1000]);

The entered values are just an example. Unfortunately setting this up can be quite tedious. For more information about how to find the correct values you can look here:

d3js scale, transform and translate