计算谷歌地图上绘制的多边形的区域javascript [英] calculate area of a drawn polygon on google map javascript
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问题描述
您好，我必须计算谷歌地图上绘制的多边形的面积。
jsfiddle http://jsfiddle.net/tvqzd/4/
我使用
var area = google.maps.geometry.spherical.computeArea （newShape.getPath（））;
但是我希望它在按钮点击时计算
和多边形是可编辑的。如果我改变/编辑区域怎么办？我可以在areachange事件上获取区域吗？
解决方案
您需要侦听多边形路径上的set_at和insert_at事件，重新计算其中一个触发区域。
http://jsfiddle.net/geocodezip/hk82v0zp/2/
< >代码段：
$ b
＃map，html，body {padding：0;保证金：0; height：100％;}＃panel {width：200px; font-family：Arial，sans-serif; font-size：13px; float：right; margin：10px;}＃color-palette {clear：both;}。color-button {width：14px;身高：14px; font-size：0; margin：2px;向左飘浮; cursor：pointer;}＃delete-button {margin-top：5px;}
< script src =https://maps.googleapis.com/maps/api/js?libraries=geometry,drawing>< / script>< title>绘图工具< / title> < div id =panel> < div id =color-palette>< / div> < DIV> < button id =delete-button>删除所选形状< / button> < button id =calculateonClick =calcar（）>计算面积< /按钮> < div id =area>< / div> < / div>< / div>< div id =map>< / div>
Hi there I have to calculate the area of drawn polygon on google map . jsfiddle http://jsfiddle.net/tvqzd/4/
I calculate it using
var area = google.maps.geometry.spherical.computeArea(newShape.getPath());
but I want it to be Calculated on button click
and polygon is editable . What if I change/edit area ? Can I get the area on areachange event or something?
解决方案
You need to listen for the set_at and insert_at events on the polygon path, recalculate the area when one of them fires.
Description of user editable shape events in the documentation
Example: http://jsfiddle.net/geocodezip/hk82v0zp/2/
code snippet:
var drawingManager;
var selectedShape;
var colors = ['#1E90FF', '#FF1493', '#32CD32', '#FF8C00', '#4B0082'];
var selectedColor;
var colorButtons = {};
function clearSelection() {
if (selectedShape) {
selectedShape.setEditable(false);
selectedShape = null;
}
}
function setSelection(shape) {
clearSelection();
selectedShape = shape;
shape.setEditable(true);
selectColor(shape.get('fillColor') || shape.get('strokeColor'));
google.maps.event.addListener(shape.getPath(), 'set_at', calcar);
google.maps.event.addListener(shape.getPath(), 'insert_at', calcar);
}
function calcar() {
var area = google.maps.geometry.spherical.computeArea(selectedShape.getPath());
document.getElementById("area").innerHTML = "Area =" + area.toFixed(2);
}
function deleteSelectedShape() {
if (selectedShape) {
selectedShape.setMap(null);
}
}
function selectColor(color) {
selectedColor = color;
for (var i = 0; i < colors.length; ++i) {
var currColor = colors[i];
colorButtons[currColor].style.border = currColor == color ? '2px solid #789' : '2px solid #fff';
}
// Retrieves the current options from the drawing manager and replaces the
// stroke or fill color as appropriate.
var polylineOptions = drawingManager.get('polylineOptions');
polylineOptions.strokeColor = color;
drawingManager.set('polylineOptions', polylineOptions);
var rectangleOptions = drawingManager.get('rectangleOptions');
rectangleOptions.fillColor = color;
drawingManager.set('rectangleOptions', rectangleOptions);
var circleOptions = drawingManager.get('circleOptions');
circleOptions.fillColor = color;
drawingManager.set('circleOptions', circleOptions);
var polygonOptions = drawingManager.get('polygonOptions');
polygonOptions.fillColor = color;
drawingManager.set('polygonOptions', polygonOptions);
}
function setSelectedShapeColor(color) {
if (selectedShape) {
if (selectedShape.type == google.maps.drawing.OverlayType.POLYLINE) {
selectedShape.set('strokeColor', color);
} else {
selectedShape.set('fillColor', color);
}
}
}
function makeColorButton(color) {
var button = document.createElement('span');
button.className = 'color-button';
button.style.backgroundColor = color;
google.maps.event.addDomListener(button, 'click', function() {
selectColor(color);
setSelectedShapeColor(color);
});
return button;
}
function buildColorPalette() {
var colorPalette = document.getElementById('color-palette');
for (var i = 0; i < colors.length; ++i) {
var currColor = colors[i];
var colorButton = makeColorButton(currColor);
colorPalette.appendChild(colorButton);
colorButtons[currColor] = colorButton;
}
selectColor(colors[0]);
}
function initialize() {
var map = new google.maps.Map(document.getElementById('map'), {
zoom: 10,
center: new google.maps.LatLng(22.344, 114.048),
mapTypeId: google.maps.MapTypeId.ROADMAP,
disableDefaultUI: true,
zoomControl: true
});
var polyOptions = {
strokeWeight: 0,
fillOpacity: 0.45,
editable: true
};
// Creates a drawing manager attached to the map that allows the user to draw
// markers, lines, and shapes.
drawingManager = new google.maps.drawing.DrawingManager({
drawingMode: google.maps.drawing.OverlayType.POLYGON,
markerOptions: {
draggable: true
},
polylineOptions: {
editable: true
},
rectangleOptions: polyOptions,
circleOptions: polyOptions,
polygonOptions: polyOptions,
map: map
});
google.maps.event.addListener(drawingManager, 'overlaycomplete', function(e) {
if (e.type != google.maps.drawing.OverlayType.MARKER) {
// Switch back to non-drawing mode after drawing a shape.
drawingManager.setDrawingMode(null);
// Add an event listener that selects the newly-drawn shape when the user
// mouses down on it.
var newShape = e.overlay;
newShape.type = e.type;
google.maps.event.addListener(newShape, 'click', function() {
setSelection(newShape);
});
var area = google.maps.geometry.spherical.computeArea(newShape.getPath());
document.getElementById("area").innerHTML = "Area =" + area.toFixed(2);
setSelection(newShape);
}
});
// Clear the current selection when the drawing mode is changed, or when the
// map is clicked.
google.maps.event.addListener(drawingManager, 'drawingmode_changed', clearSelection);
google.maps.event.addListener(map, 'click', clearSelection);
google.maps.event.addDomListener(document.getElementById('delete-button'), 'click', deleteSelectedShape);
buildColorPalette();
}
google.maps.event.addDomListener(window, 'load', initialize);
#map,
html,
body {
padding: 0;
margin: 0;
height: 100%;
}
#panel {
width: 200px;
font-family: Arial, sans-serif;
font-size: 13px;
float: right;
margin: 10px;
}
#color-palette {
clear: both;
}
.color-button {
width: 14px;
height: 14px;
font-size: 0;
margin: 2px;
float: left;
cursor: pointer;
}
#delete-button {
margin-top: 5px;
}
<script src="https://maps.googleapis.com/maps/api/js?libraries=geometry,drawing"></script>
<title>Drawing Tools</title>
<div id="panel">
<div id="color-palette"></div>
<div>
<button id="delete-button">Delete Selected Shape</button>
<button id="calculate" onClick="calcar()">calculate area</button>
<div id="area"></div>
</div>
</div>
<div id="map"></div>
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