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Geometry Service - Calculate geometry
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Description
This example shows how you can use an ArcGIS Server geometry service to measure polygon areas and perimeter lengths in your Web application. When you draw a polygon with the mouse, the Draw toolbar captures the polygon's geometry. This sample passes the geometry to the GeometryService.areasAndLengths() method.
Because this map uses a projected coordinate system that is appropriate for calculating lengths and areas, no projection of the polygon is necessary. If your map is in a geographic coordinate system and you need to project the polygon before measuring, see the sample Measure distances to learn how to perform the projection with the geometry service.
Code
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
<title>Measure Polygon Area and Perimeter</title>
<link rel="stylesheet" href="https://js.arcgis.com/3.29/esri/css/esri.css">
<style>
html, body, #mapDiv {
height: 100%;
margin: 0;
padding: 0;
width: 100%;
}
#info {
bottom: 20px;
color: #444;
height: auto;
font-family: arial;
left: 20px;
margin: 5px;
padding: 10px;
position: absolute;
text-align: left;
width: 200px;
z-index: 40;
}
.label {
display: inline-block;
width: 4em;
}
</style>
<script src="https://js.arcgis.com/3.29/"></script>
<script>
require(["dojo/dom",
"dojo/_base/lang",
"dojo/json",
"esri/config",
"esri/map",
"esri/graphic",
"esri/geometry/Geometry",
"esri/geometry/Extent",
"esri/SpatialReference",
"esri/tasks/GeometryService",
"esri/tasks/AreasAndLengthsParameters",
"esri/toolbars/draw",
"esri/symbols/SimpleFillSymbol"],
function(dom, lang, json, esriConfig, Map, Graphic, Geometry, Extent, SpatialReference, GeometryService, AreasAndLengthsParameters, Draw, SimpleFillSymbol){
//identify proxy page to use if the toJson payload to the geometry service is greater than 2000 characters.
//If this null or not available the project and lengths operation will not work. Otherwise it will do a http post to the proxy.
esriConfig.defaults.io.proxyUrl = "/proxy/";
esriConfig.defaults.io.alwaysUseProxy = false;
var map = new Map("mapDiv", {
basemap: "topo",
center: [-122.778, 45.483],
zoom: 15
});
map.on("load", function() {
var tb = new Draw(map);
tb.on("draw-end", lang.hitch(map, getAreaAndLength));
tb.activate(Draw.FREEHAND_POLYGON);
});
var geometryService = new GeometryService("https://sampleserver6.arcgisonline.com/arcgis/rest/services/Utilities/Geometry/GeometryServer");
geometryService.on("areas-and-lengths-complete", outputAreaAndLength);
function getAreaAndLength(evtObj) {
var map = this,
geometry = evtObj.geometry;
map.graphics.clear();
var graphic = map.graphics.add(new Graphic(geometry, new SimpleFillSymbol()));
//setup the parameters for the areas and lengths operation
var areasAndLengthParams = new AreasAndLengthsParameters();
areasAndLengthParams.lengthUnit = GeometryService.UNIT_FOOT;
areasAndLengthParams.areaUnit = GeometryService.UNIT_ACRES;
areasAndLengthParams.calculationType = "geodesic";
geometryService.simplify([geometry], function(simplifiedGeometries) {
areasAndLengthParams.polygons = simplifiedGeometries;
geometryService.areasAndLengths(areasAndLengthParams);
});
}
function outputAreaAndLength(evtObj) {
var result = evtObj.result;
console.log(json.stringify(result));
dom.byId("area").innerHTML = result.areas[0].toFixed(3) + " acres";
dom.byId("length").innerHTML = result.lengths[0].toFixed(3) + " feet";
}
});
</script>
</head>
<body>
<div id="mapDiv"></div>
<div id="info" class="esriSimpleSlider">
Draw a polygon to be used as input to the geometryService's areasAndLengths() operation.
<br><br>
<span class="label">Area:</span> <span id="area"></span>
<br>
<span class="label">Length:</span> <span id="length"></span>
</div>
</body>
</html>