topic Buffering Points and Polygons in ArcGIS REST APIs and Services Questions

Buffering Points and Polygons

JasonCleaver — Thu, 21 Nov 2013 11:31:22 GMT

I am looking for help as to what to plug into the buffer params to get accurate results.

What values should I pass to the buffer service to accurately create a 100 foot buffer around a polygon or polyline when the inSR and ourSR equal 101200?

Looking at the API, if the bufferSR is GCS then the units has to be in decimal degress, however this is a project coordinate system.

Do I have to change the bufferSR to something other than 102100?
Do I have to set the geodesic to true?
Do I have to re-project the geometry first and then perform the buffer?

Thanks,

Jason

Re: Buffering Points and Polygons

SimonLiu — Tue, 10 Dec 2013 09:09:36 GMT

Hi Jason,

The most important thing is to set geodesic to true. This will create an accurate buffer from projected units and the bufferSR parameter will be ignored.

If you have Web Mercator input geometries, the inSR and outSR should both be set to 102100. In addition, make sure that you specify the buffer unit correctly. The US survey foot has a WKID of 9003 and the international foot is 9002.

http://resources.arcgis.com/en/help/arcobjects-cpp/componenthelp/000w/000w00000042000000.htm