谷歌地图在一个多边形内绘制一个更小的多边形
问题描述:
所以我试图渲染谷歌地图上的形状(使用V3的API),其中包含相同的形状,只是更小的内部。基本上是一个盒子或一个多边形内的多边形。谷歌地图在一个多边形内绘制一个更小的多边形
对于矩形我有以下的代码,它的工作原理:
var drawEdgesRectangle = function (shape) {
// shape is the original, parent rectangle
var NE, SW, childNE, childSW, padding, diagonal, inner;
// set padding constant to 1 (i.e. 1m distance all around)
padding = 1;
// get diagonal distance from corner
diagonal = Math.sqrt(2) * padding;
// get NE of parent
NE = shape.bounds.getNorthEast();
// get SW of parent
SW = shape.bounds.getSouthWest();
// get child NE, SW
childNE = google.maps.geometry.spherical.computeOffset(NE, diagonal, 225);
childSW = google.maps.geometry.spherical.computeOffset(SW, diagonal, 45);
// render inner shape
inner = new google.maps.Rectangle({
strokeColor: 'white',
strokeOpacity: 0.8,
strokeWeight: 1,
fillColor: 'black',
fillOpacity: 0.35,
map: map,
bounds: new google.maps.LatLngBounds(
childSW,
childNE
)
});
}
当然,这样做了多边形是鱼的不同水壶。我知道我可以使用getPaths()
来获得每一行的属性,但是要弄清楚如何放置内部行,并且确实找出'内部'在哪里对我来说在概念上是相当困难的。
我想知道我想要达到的目标是否可能给予谷歌API,并希望如何解决它的任何指针。
答
如果多边形是“简单的”(中心是“内部”多边形且没有凹面),那么可以采取类似于矩形的操作(这是一个四边形多边形而符合这些标准):
包括它:
<script src="https://maps.googleapis.com/maps/api/js?v=3&libraries=geometry"></script>
代码(假定全球 “聚” 等):
var drawEdgesPoly = function() {
// shape is the original, parent polygon
var shape = poly;
// set padding constant to 1 (i.e. 1m distance all around)
padding = 50;
var vertices = shape.getPath();
var polybounds = new google.maps.LatLngBounds();
for (var i = 0; i < vertices.getLength(); i++) {
polybounds.extend(vertices.getAt(i));
}
var center = polybounds.getCenter();
if (centerMarker && centerMarker.setMap) {
centerMarker.setMap(null);
}
centerMarker = new google.maps.Marker({
position: center,
map: map,
icon: {
url: "https://maps.gstatic.com/intl/en_us/mapfiles/markers2/measle.png",
size: new google.maps.Size(7, 7),
anchor: new google.maps.Point(4, 4)
}
});
if (polylines && (polylines.length > 0)) {
for (var i = 0; i < polylines.length; i++) {
polylines[i].setMap(null);
}
}
polylines = [];
var newPath = [];
for (var i = 0; i < vertices.getLength(); i++) {
polylines.push(new google.maps.Polyline({
path: [center, vertices.getAt(i)],
map: map,
strokeWidth: 2,
strokeColor: 'red'
}));
newPath[i] = google.maps.geometry.spherical.computeOffset(vertices.getAt(i),
padding,
google.maps.geometry.spherical.computeHeading(vertices.getAt(i), center));
}
if (inner && inner.setMap)
inner.setMap(null);
// render inner shape
inner = new google.maps.Polygon({
strokeColor: 'white',
strokeOpacity: 0.8,
strokeWeight: 1,
fillColor: 'black',
fillOpacity: 0.35,
map: map,
editable: false,
path: newPath
});
};
proof of concept fiddle 用代码片段或jsfiddle中的多边形播放来查看约束。
var map;
var infoWindow;
var poly;
var inner;
var polylines = [];
var centerMarker;
var paths = [
[
new google.maps.LatLng(38.872886, -77.054720),
new google.maps.LatLng(38.872602, -77.058046),
new google.maps.LatLng(38.870080, -77.058604),
new google.maps.LatLng(38.868894, -77.055664),
new google.maps.LatLng(38.870598, -77.053346)
]
];
function initialize() {
var mapOptions = {
center: new google.maps.LatLng(38.8714, -77.0556),
zoom: 15
};
map = new google.maps.Map(document.getElementById('map-canvas'), mapOptions);
poly = new google.maps.Polygon({
paths: paths,
strokeWeight: 3,
fillColor: '#55FF55',
fillOpacity: 0.5,
editable: true
});
poly.setMap(map);
drawEdgesPoly();
google.maps.event.addListener(poly.getPath(), 'insert_at', drawEdgesPoly);
google.maps.event.addListener(poly.getPath(), 'remove_at', drawEdgesPoly);
google.maps.event.addListener(poly.getPath(), 'set_at', drawEdgesPoly);
// Define an info window on the map.
infoWindow = new google.maps.InfoWindow();
}
google.maps.event.addDomListener(window, 'load', initialize);
var drawEdgesPoly = function() {
// shape is the original, parent polygon
var shape = poly;
// set padding constant to 1 (i.e. 1m distance all around)
padding = 50;
var vertices = shape.getPath();
var polybounds = new google.maps.LatLngBounds();
for (var i = 0; i < vertices.getLength(); i++) {
polybounds.extend(vertices.getAt(i));
}
var center = polybounds.getCenter();
if (centerMarker && centerMarker.setMap) {
centerMarker.setMap(null);
}
centerMarker = new google.maps.Marker({
position: center,
map: map,
icon: {
url: "https://maps.gstatic.com/intl/en_us/mapfiles/markers2/measle.png",
size: new google.maps.Size(7, 7),
anchor: new google.maps.Point(4, 4)
}
});
if (polylines && (polylines.length > 0)) {
for (var i = 0; i < polylines.length; i++) {
polylines[i].setMap(null);
}
}
polylines = [];
var newPath = [];
for (var i = 0; i < vertices.getLength(); i++) {
polylines.push(new google.maps.Polyline({
path: [center, vertices.getAt(i)],
map: map,
strokeWidth: 2,
strokeColor: 'red'
}));
newPath[i] = google.maps.geometry.spherical.computeOffset(vertices.getAt(i),
padding,
google.maps.geometry.spherical.computeHeading(vertices.getAt(i), center));
}
if (inner && inner.setMap)
inner.setMap(null);
// render inner shape
inner = new google.maps.Polygon({
strokeColor: 'white',
strokeOpacity: 0.8,
strokeWeight: 1,
fillColor: 'black',
fillOpacity: 0.35,
map: map,
editable: false,
path: newPath
});
};
html,
body,
#map-canvas {
height: 100%;
width: 100%;
}
<script src="https://maps.googleapis.com/maps/api/js?v=3&libraries=geometry"></script>
<div id="map-canvas" style="height:100%; width:100%;"></div>
+0
哇。非常感谢。这正是我需要的。奖金标记用于突出显示小提琴中的多边形'set_at','insert_at'和'remove_at'事件。做得好。 – 2014-09-24 18:26:35
有多复杂,你需要做的多边形?他们是武断的吗? – geocodezip 2014-09-24 00:15:31
理想情况下,我想接受任何类型的多边形。在现实中,问题不大可能包含10行以上。 – 2014-09-24 00:18:42
线/顶点的数量不是复杂度的真正度量。有没有凹面?多边形内多边形的中心?如果是这样(并且没有凹边),你应该可以做类似于你为矩形做的事情。 – geocodezip 2014-09-24 00:40:56