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mapPoint = esri.geometry.geographicToWebMercator(new esri.geometry.Point(position.coords.longitude, position.coords.latitude, new esri.SpatialReference({ wkid: 4326 }))); //Changed this line to include "esri.geometry.geographicToWebMercator("
var graphicCollection = new esri.geometry.Multipoint(new esri.SpatialReference({ wkid: 102100 })); //changed wkid: 102100 Web Mercator