topic When to use &amp;quot;project&amp;quot; when calculating areas and lengths? in ArcGIS JavaScript Maps SDK Questions https://community.esri.com/t5/arcgis-javascript-maps-sdk-questions/when-to-use-amp-quot-project-amp-quot-when/m-p/5672#M521 <HTML><HEAD></HEAD><BODY><SPAN>Newbie here. I'm in the process of converting a Flex viewer to Javascript and currently working on a Draw and Measure widget. I noticed in the Flex version that a call to "project" is being made before the call to calculate lengths. I'm trying to understand when and why this needs to be called as opposed to just calling the "lengths" function of the GeometryService.&nbsp; According to the sample documentation for the Javascript API the "Measure distances" sample is supposed to be using "project" but when I look at the sample code it is just calling the "lengths" function of GeometryService.&nbsp; I understand it has something to do with the coordinate system being used by the map but if someone could provide some more detail for me on when to call "project" it would be very helpful. Thanks.</SPAN></BODY></HTML> Fri, 23 May 2014 12:24:35 GMT StanLambert 2014-05-23T12:24:35Z When to use &quot;project&quot; when calculating areas and lengths? https://community.esri.com/t5/arcgis-javascript-maps-sdk-questions/when-to-use-amp-quot-project-amp-quot-when/m-p/5672#M521 <HTML><HEAD></HEAD><BODY><SPAN>Newbie here. I'm in the process of converting a Flex viewer to Javascript and currently working on a Draw and Measure widget. I noticed in the Flex version that a call to "project" is being made before the call to calculate lengths. I'm trying to understand when and why this needs to be called as opposed to just calling the "lengths" function of the GeometryService.&nbsp; According to the sample documentation for the Javascript API the "Measure distances" sample is supposed to be using "project" but when I look at the sample code it is just calling the "lengths" function of GeometryService.&nbsp; I understand it has something to do with the coordinate system being used by the map but if someone could provide some more detail for me on when to call "project" it would be very helpful. Thanks.</SPAN></BODY></HTML> Fri, 23 May 2014 12:24:35 GMT https://community.esri.com/t5/arcgis-javascript-maps-sdk-questions/when-to-use-amp-quot-project-amp-quot-when/m-p/5672#M521 StanLambert 2014-05-23T12:24:35Z