使用Google Maps API v3访问嵌套的geojson文件中的坐标以绘制多边形

Question

I am having a real pain of trying to draw multiple polygons from a geojson file. Below I have pasted a sample of the geojson file and the javascript used to access it. It seems the main problem I am running into is that I cannot get into that array of coordinates nested in each record as it either returns the error that "coordinates" is undefined or that there is no method "setMap" for undefined. I have been able to return other nested aspects of a similar JSON file (this is a test file, the real one actually has data, just trying to get the polygon drawing here), but getting those coordinates is not working. I am not a javascript master so I can't tell where the code is failing to make the proper access.

thanks in advance.

the json data looks like this:

var data={
    "type": "FeatureCollection",
    "features": [
        {
            "type": "Feature",
            "id": 1,
            "properties": {
                "Name": "",
                "description": "",
                "timestamp": "",
                "begin": "",
                "end": "",
                "altitudeMode": "clampToGround",
                "tessellate": 1,
                "extrude": -1,
                "visibility": -1
            },
            "geometry": {
                "type": "Polygon",
                "coordinates": [
                    [
                        [
                            -83.126571,
                            42.348706
                        ],
                        [
                            -83.126520,
                            42.348634
                        ],
                        [
                            -83.126516,
                            42.348635
                        ],
                        [
                            -83.126147,
                            42.348778
                        ],
                        [
                            -83.126144,
                            42.348780
                        ],
                        [
                            -83.126195,
                            42.348852
                        ],
                        [
                            -83.126199,
                            42.348851
                        ],
                        [
                            -83.126568,
                            42.348708
                        ],
                        [
                            -83.126571,
                            42.348706
                        ]
                    ]
                ]
            }
        },
        {
            "type": "Feature",
            "id": 2,
            "properties": {
                "Name": "",
                "description": "",
                "timestamp": "",
                "begin": "",
                "end": "",
                "altitudeMode": "clampToGround",
                "tessellate": 1,
                "extrude": -1,
                "visibility": -1
            },
            "geometry": {
                "type": "Polygon",
                "coordinates": [
                    [
                        [
                            -83.132805,
                            42.356496
                        ],
                        [
                            -83.132753,
                            42.356423
                        ],
                        [
                            -83.132751,
                            42.356424
                        ],
                        [
                            -83.132243,
                            42.356624
                        ],
                        [
                            -83.132241,
                            42.356625
                        ],
                        [
                            -83.132294,
                            42.356698
                        ],
                        [
                            -83.132296,
                            42.356697
                        ],
                        [
                            -83.132802,
                            42.356497
                        ],
                        [
                            -83.132805,
                            42.356496
                        ]
                    ]
                ]
            }
        },
        {
            "type": "Feature",
            "id": 3,
            "properties": {
                "Name": "",
                "description": "",
                "timestamp": "",
                "begin": "",
                "end": "",
                "altitudeMode": "clampToGround",
                "tessellate": 1,
                "extrude": -1,
                "visibility": -1
            },
            "geometry": {
                "type": "Polygon",
                "coordinates": [
                    [
                        [
                            -83.126776,
                            42.351813
                        ],
                        [
                            -83.126492,
                            42.351413
                        ],
                        [
                            -83.126189,
                            42.351525
                        ],
                        [
                            -83.126191,
                            42.351528
                        ],
                        [
                            -83.126376,
                            42.351807
                        ],
                        [
                            -83.126776,
                            42.351813
                        ]
                    ]
                ]
            }
        }
    etc...
    ]
}

I've got the javascript as below, using the example used at geojason.info: http://demos.geojason.info/complex-geojson-polygons-google-maps-demo.php

var points;
var pointsMore;
var polygon;
var map;


function initializeMap() {

    map = new google.maps.Map(document.getElementById("map_canvas"), {
        zoom: 11,
        center: new google.maps.LatLng(42.347727, -83.058014),
        mapTypeId: google.maps.MapTypeId.TERRAIN
    });

    var polygon = createPolygons(pointsMore);
    //this is where the problem is...check nesting.
    polygon.setMap(map);

}


function createPolygons(pointsMore) {
    for (var y = 0; y < data.features.length; y++) {
        var points = data.features[y];
        for (var z = 0; points.geometry.length; z++) {
            var pointsMore = points.geometry[z];



    var coords = pointsMore.coordinates;
    var paths = [];
    $.each(coords,function(i,n){
        $.each(n, function(j,o){
           var path = [];
           $.each(o,function(k,p){
               var ll = new google.maps.LatLng(p[1],[0]);
               path.push(ll);
           });
           paths.push(path); 
        });
    });
    var polygon = new google.maps.Polygon({
        paths: paths,
        strokeColor: "#FF7800",
        strokeOpacity: 1,
        strokeWeight: 2,
        fillColor: "#46461F",
        fillOpacity: 0.25
    });
    return polygon; 
        }   
    }
}

Answer 1

points.geometry is an object, but you're trying to loop through it like an array. To access the coordinates, use:

var coordinates = data.features[y].geometry.coordinates;

Answer 2

I'm prefering to integrate the geojson data => map.data.addGeoJson(data); where data is simply your js var containing the features details. here's an example of initialize() function :

function initialize() {


   // Create a simple map.
    map = new google.maps.Map(document.getElementById('map_canvas'), {
        zoom: 11,
        center: {
            lat: 42.347727,
            lng: -83.058014
        },
        mapTypeId: google.maps.MapTypeId.TERRAIN
    });

    // Load a GeoJSON from the same server as our demo.
    map.data.addGeoJson(mapdata);

    setStyle();

};

Answer 3

Here is the code to get coordinate

var coordinates = data.features[0].geometry.coordinates;

There maybe more than one arrays

var first = data.features[0].geometry.coordinates[0];
var second= data.features[0].geometry.coordinates[1];