Hi Aditi,
Below is an example on how you can buffer a feature using a button:
<!DOCTYPE html>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<!--The viewport meta tag is used to improve the presentation and behavior of the samples
on iOS devices-->
<meta name="viewport" content="initial-scale=1, maximum-scale=1,user-scalable=no">
<title>Sample Map</title>
<link rel="stylesheet" href="http://js.arcgis.com/3.12/dijit/themes/claro/claro.css">
<link rel="stylesheet" href="http://js.arcgis.com/3.12/esri/css/esri.css">
<style>
html, body, #mapDiv {
padding:0;
margin:0;
height:100%;
}
#button{
position: absolute;
top: 50px;
left: 100px;
z-index: 5;
}
</style>
<script src="http://js.arcgis.com/3.12/"></script>
<script>
var map, graphic;
require([
"esri/map", "esri/layers/FeatureLayer", "esri/symbols/SimpleMarkerSymbol", "esri/symbols/SimpleFillSymbol", "esri/geometry/Point",
"esri/graphic", "dojo/_base/Color", "esri/symbols/SimpleLineSymbol", "esri/tasks/GeometryService",
"esri/tasks/BufferParameters", "esri/SpatialReference",
"dojo/dom", "dojo/on", "dojo/_base/array", "dojo/parser", "dojo/domReady!"
], function(
Map, FeatureLayer, SimpleMarkerSymbol, SimpleFillSymbol, Point,
Graphic, Color, SimpleLineSymbol, GeometryService,
BufferParameters, SpatialReference,
dom, on, array, parser
) {
parser.parse();
map = new Map("mapDiv", {
basemap: "streets",
center: [-81.792107, 26.150807],
zoom: 8
});
gs = new GeometryService("http://utility.arcgisonline.com/ArcGIS/rest/services/Geometry/GeometryServer");
var featureLayer = new FeatureLayer("http://sampleserver6.arcgisonline.com/arcgis/rest/services/USA/MapServer/0",{
mode: FeatureLayer.MODE_ONDEMAND,
outFields: ["*"]
});
var symbol = new SimpleMarkerSymbol(
SimpleMarkerSymbol.STYLE_CIRCLE,
12,
new SimpleLineSymbol(
SimpleLineSymbol.STYLE_NULL,
new Color([247, 34, 101, 0.9]),
1
),
new Color([207, 34, 171, 0.5])
);
on(featureLayer, "click", function(evt){
map.graphics.clear();
xloc = evt.graphic.geometry.x;
yloc = evt.graphic.geometry.y;
var pt = new Point(xloc,yloc,map.spatialReference)
graphic = new Graphic(pt, symbol);
map.graphics.add(graphic);
})
map.addLayer(featureLayer);
on(dom.byId("buffer"), 'click', function(evt){
var params = new BufferParameters();
params.distances = [10];
params.bufferSpatialReference = map.spatialReference;
params.outSpatialReference = map.spatialReference;
params.unit = GeometryService.UNIT_STATUTE_MILE
console.log(graphic);
params.geometries = [graphic.geometry];
console.log(params);
gs.buffer(params, showBuffer);
})
function showBuffer(bufferedGeometries) {
console.log(bufferedGeometries);
var symbol = new SimpleFillSymbol("none", new SimpleLineSymbol("dashdot", new Color([255, 0, 0]), 2), new Color([255, 255, 0, 0.25]));
array.forEach(bufferedGeometries, function (geometry) {
graphic = new Graphic(geometry, symbol);
map.graphics.add(graphic);
});
}
});
</script>
</head>
<body class='claro'>
<div id="mapDiv">
<div id="button">
<button data-dojo-type="dijit/form/Button" id='buffer'>Buffer</button>
</div>
</div>
</body>
</html>
