2

我非常痛苦地尝试从 geojson 文件中绘制多个多边形。下面我粘贴了 geojson 文件的示例和用于访问它的 javascript。我遇到的主要问题似乎是我无法进入嵌套在每条记录中的坐标数组，因为它要么返回“坐标”未定义的错误，要么没有未定义的“setMap”方法。我已经能够返回类似 JSON 文件的其他嵌套方面（这是一个测试文件，真正的文件实际上有数据，只是想在这里获取多边形图），但是获取这些坐标不起作用。我不是 javascript 大师，所以我不知道代码在哪里无法正确访问。

提前致谢。

json 数据如下所示：

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...
    ]
}

我有下面的 javascript，使用 geojason.info 中使用的示例：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; 
        }   
    }
}
4

3 回答 3

5

points.geometry是一个对象，但你试图像数组一样循环遍历它。要访问坐标，请使用：

var coordinates = data.features[y].geometry.coordinates;
于 2011-09-12T15:25:33.490 回答
1

我更喜欢集成geojson数据=>map.data.addGeoJson(data);其中data只是您的js var包含功能详细信息。这是一个initialize()函数示例：

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();

};
于 2014-11-07T18:06:54.163 回答
0

这是获取坐标的代码

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

可能有不止一个数组

var first = data.features[0].geometry.coordinates[0];
var second= data.features[0].geometry.coordinates[1];
于 2018-06-25T01:42:12.993 回答