Question

我正在使用OpenLayers并加载一些完美运行的GEOJson文件。现在我希望能够选择GEOJson文件的各个组件。例如，当我激活悬停选择时，如果我有多个要素（几个多边形），则没有任何反应。

我将悬停选择器添加到此示例http://openlayers.org/dev/examples/geojson.html

我实际上可以单独拖动元素但我无法选择它们。我认为这是因为我正在使用的投影。任何想法如何解决它？

干杯！

function init(){

var options = {
    projection: new OpenLayers.Projection("EPSG:900913"),
    displayProjection: new OpenLayers.Projection("EPSG:4326"),
    units: "m",
    numZoomLevels: 18,
};

map = new OpenLayers.Map('map', options );
var mapnik = new OpenLayers.Layer.OSM({layers: 'basic'});           
map.addLayer(mapnik);

map.addControl(new OpenLayers.Control.MousePosition());

var lon = 12.18;
var lat = 53.81;
var lonLat = new OpenLayers.LonLat(lon,lat).transform(map.displayProjection,  map.projection);

var mapcent = new OpenLayers.LonLat(lon, lat).transform(map.displayProjection, map.projection);
zoom = 5.5;
map.setCenter(mapcent, zoom);
document.getElementById('noneToggle').checked = true;

var proj = new OpenLayers.Projection("EPSG:4326");

var file = [];
file[0] = "geojson/nuts3.geojson";

var style = [];

i=0;
while(i<file.length){
    style[i] = new OpenLayers.StyleMap({
        pointRadius: 2,
        strokeColor: 'red',
        strokeWidth: 1,
        strokeOpacity: 1,
        fillColor: 'red',
        fillOpacity: 0.2
    });

    var layer_name = "layer_" + i;
    vectorLayer[i] = new OpenLayers.Layer.Vector(layer_name,  {
        styleMap: style[i],
        projection: map.displayProjection,
        preFeatureInsert: function(feature){
        feature.geometry.transform(proj, map.getProjectionObject());
        },
    });
    map.addLayer(vectorLayer[i]);   

    var gjson = new OpenLayers.Format.GeoJSON();
    var featurecollection = ReadFile(file[i]);
    //Readfile is just a normal Request.POST function   
    vectorLayer[i].addFeatures(gjson.read(featurecollection));  
    i=i+1;
}

controls = {
    selecthover: new OpenLayers.Control.SelectFeature(vectorLayer[0],{
        hover: true,
        highlightOnly: true
    })
};

for(var key in controls) {
    map.addControl(controls[key]);
    controls[key].activate();

}

            var report = function(e) {
            OpenLayers.Console.log(e.type, e.feature.id);
        };

        var highlightCtrl = new OpenLayers.Control.SelectFeature(vectors, {
            hover: true,
            highlightOnly: true,
            renderIntent: "temporary",
            eventListeners: {
                beforefeaturehighlighted: report,
                featurehighlighted: report,
                featureunhighlighted: report
            }
        });


        map.addControl(highlightCtrl);
        map.addControl(selectCtrl);            
}

geojson文件类似于

{ “type”：“FeatureCollection”， “特征”： [ {“type”：“Feature”，“id”：0，“properties”：{}，“geometry”：{“type”：“Polygon”，“coordinates”：[[[9.244170,48.847009]，[9.246171， 48.822260]，[9.248220,48.796910]，[9.248433,48.794277]，[9.290007,48.791633]，[9.298732,48.785304]，[9.145165,48.859655]，[9.153553,48.861241]，[9.207493,48.852769]，[9.235667,48.848344] ，[9.244170,48.847009]]}} ， {“type”：“Feature”，“id”：1，“properties”：{}，“geometry”：{“type”：“Polygon”，“coordinates”：[[[9.064848,48.755577]，[9.038994， 48.741317]，[9.104720,48.709080]，[9.104721,48.709079]，[9.146561,48.663574]，[9.156822,48.652414]，[9.162166,48.646602]，[9.174173,48.633544]，[9.064848,48.755577]]}} ， ......等等。

Answer 1

好的我解决了。

https://gis.stackexchange.com/questions/25314/change-vector-projection-in-openlayers

根据该问题的正确答案中提出的投影，并对geojson文件的每个部分使用独立的id，可以在悬停时选择。

Openlayers中使用GEOJson格式的独立特征选择

1 个答案: