有没有一种方法可以使用Google地图API获取国家边界的多边形坐标值。
如果你想更好地控制边界的显示,建议使用google.maps.Data
图层,而不是Fusion表。例如,在geocodezip示例中的世界地图上,如果你缩小地图,边界将会塌陷成点,这是Fusion表和Fusion Layer的局限性之一。通过Data Layer你可以针对特定边界进行样式设置或隐藏。而Fusion Layer
只允许条件样式更改。此外,你还可以添加自己的click
、mouseover
、mouseout
监听器,实时更改边界图层等等。当然,有时候Fusion Layer
是更好的选择,例如当你的数据包含在Fusion表中时,但如果你需要更多的控制权,则Data Layer
是更值得推荐的选择。
在我的下一个工作示例中,我将展示如何使用Data Layer
渲染世界国家和美国州边界。当然,你也可以使用自己的边界文件。如果你没有GeoJson版本可用(仅有Shapefiles或KML文件),你可以使用像mapshaper之类的工具将其转换为GeoJson(只需运行:mapshaper -i myshp.shp -o format=geojson out.geo.json
)。
var map = null;
var my_boundaries = {};
var data_layer;
var info_window;
//initialize map on document ready
$(document).ready(function(){
var latlng = new google.maps.LatLng(40.723080, -73.984340); //you can use any location as center on map startup
var myOptions = {
zoom: 2,
center: latlng,
mapTypeControl: true,
mapTypeControlOptions: {style: google.maps.MapTypeControlStyle.DROPDOWN_MENU},
navigationControl: true,
mapTypeId: google.maps.MapTypeId.ROADMAP
};
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
google.maps.event.addListener(map, 'click', function(){
if(info_window){
info_window.setMap(null);
info_window = null;
}
});
$('#boundary_load_select').change(function(){
if($(this).val()==1){
loadBoundariesFromGeoJson("https://raw.githubusercontent.com/matej-pavla/Google-Maps-Examples/master/BoundariesExample/geojsons/world.countries.geo.json");
}else{
loadBoundariesFromGeoJson("https://raw.githubusercontent.com/matej-pavla/Google-Maps-Examples/master/BoundariesExample/geojsons/us.states.geo.json");
}
});
loadBoundariesFromGeoJson("https://raw.githubusercontent.com/matej-pavla/Google-Maps-Examples/master/BoundariesExample/geojsons/world.countries.geo.json");
});
function initializeDataLayer(){
if(data_layer){
data_layer.forEach(function(feature) {
data_layer.remove(feature);
});
data_layer = null;
}
data_layer = new google.maps.Data({map: map}); //initialize data layer which contains the boundaries. It's possible to have multiple data layers on one map
data_layer.setStyle({ //using set style we can set styles for all boundaries at once
fillColor: 'white',
strokeWeight: 1,
fillOpacity: 0.1
});
data_layer.addListener('click', function(e) { //we can listen for a boundary click and identify boundary based on e.feature.getProperty('boundary_id'); we set when adding boundary to data layer
var boundary_id = e.feature.getProperty('boundary_id');
var boundary_name = "NOT SET";
if(boundary_id && my_boundaries[boundary_id] && my_boundaries[boundary_id].name) boundary_name = my_boundaries[boundary_id].name;
if(info_window){
info_window.setMap(null);
info_window = null;
}
info_window = new google.maps.InfoWindow({
content: '<div>You have clicked a boundary: <span style="color:red;">' + boundary_name + '</span></div>',
size: new google.maps.Size(150,50),
position: e.latLng, map: map
});
});
data_layer.addListener('mouseover', function(e) {
data_layer.overrideStyle(e.feature, {
strokeWeight: 3,
strokeColor: '#ff0000'
});
});
data_layer.addListener('mouseout', function(e) {
data_layer.overrideStyle(e.feature, {
strokeWeight: 1,
strokeColor: ''
});
});
}
function loadBoundariesFromGeoJson(geo_json_url){
initializeDataLayer();
$.getJSON(geo_json_url, function(data){
if(data.type == "FeatureCollection"){ //we have a collection of boundaries in geojson format
if(data.features){
for(var i = 0; i < data.features.length; i++){
var boundary_id = i + 1;
var new_boundary = {};
if(!data.features[i].properties) data.features[i].properties = {};
data.features[i].properties.boundary_id = boundary_id; //we will use this id to identify boundary later when clicking on it
data_layer.addGeoJson(data.features[i], {idPropertyName: 'boundary_id'});
new_boundary.feature = data_layer.getFeatureById(boundary_id);
if(data.features[i].properties.name) new_boundary.name = data.features[i].properties.name;
if(data.features[i].properties.NAME) new_boundary.name = data.features[i].properties.NAME;
my_boundaries[boundary_id] = new_boundary;
}
}
if(my_boundaries[24]){ //just an example, that you can change styles of individual boundary
data_layer.overrideStyle(my_boundaries[24].feature, {
fillColor: '#0000FF',
fillOpacity: 0.9
});
}
}
});
}
<script src="https://ajax.googleapis.com/ajax/libs/jquery/1.11.1/jquery.min.js"></script>
<script type="text/javascript" src="http://www.google.com/jsapi"></script>
<script type="text/javascript">
google.load("maps", "3",{other_params:"sensor=false"});
</script>
<body style="margin:0px; padding:0px;" >
<select id="boundary_load_select">
<option value="1">Load World Boundaries</option>
<option value="2">Load US States Boundaries</option>
</select>
<div id="map_canvas" style="height:400px; width:500px;"></div>
</body>
参考这个类似的问题:Google Maps V3: Draw German State Polygons?
FusionTables中的自然地球数据集中包含有国家多边形。您可以按照您的喜好来设计它们。
我用它创建了这个例子:http://www.geocodezip.com/v3_FusionTablesLayer_worldmap_linkto.html
这是一个使用KmlLayer的例子:http://www.geocodezip.com/v3_GoogleEx_layer-kml_world_countries_simple.html
代码片段:
var kmlLayer = null;
var map = null;
function openIW(layerEvt) {
if (layerEvt.row) {
var content = layerEvt.row['admin'].value;
} else if (layerEvt.featureData) {
var content = layerEvt.featureData.name;
}
document.getElementById('info').innerHTML = "you clicked on:<br>" + content;
}
function initialize() {
var chicago = new google.maps.LatLng(36.4278, -15.9);
var myOptions = {
zoom: 0,
center: chicago,
mapTypeId: google.maps.MapTypeId.ROADMAP
}
map = new google.maps.Map(document.getElementById("map_canvas"), myOptions);
google.maps.event.addListener(map, "click", function() {
document.getElementById('info').innerHTML = "";
});
kmlLayer = new google.maps.KmlLayer('http://www.geocodezip.com/geoxml3_test/world_countries_kml.xml', {
preserveViewport: true,
suppressInfoWindows: true
});
kmlLayer.setMap(map);
google.maps.event.addListener(kmlLayer, 'click', openIW);
}
google.maps.event.addDomListener(window, 'load', initialize);
<script src="https://maps.googleapis.com/maps/api/js?key=AIzaSyCkUOdZ5y7hMm0yrcCQoCvLwzdM6M8s5qk"></script>
<table>
<tr>
<td>
<div id="map_canvas" style="height:200px; width:300px;"></div>
</td>
<td>
<div id="info"></div>
</td>
</tr>
</table>
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吗?我不明白你所说的“我想为绘图提供一个列表”的意思(但这不是评论的主题,而是一个新问题)。 - geocodezip我猜你想在边界上绘制多边形。为此,您必须知道将帮助绘制多边形的坐标。我只为美国做过这件事。我拥有所有州的坐标。我在每个州上绘制多边形。这使美国突出显示。
您可以查看我的问题以获取美国解决方案。但是对于其他国家,您必须了解坐标。