I am using the ESRI javascript API and I have a set of lat/long points I need to convert to a state plane coordinate system. My spatial reference is wkid 3418.

I can easily use the GeometryService to project the state plane to lat/long, but need to go in the opposite direction.

I was looking at the REST API for ArcGIS and saw a setting transformFoward. Is this the setting I need to go in that direction? (http://resources.arcgis.com/en/help/arcgis-rest-api/index.html#//02r3000000pv000000)

What are ways I can do this conversion?

  • 1
    The geometry by default should be using 4326, but instead assign it 4269 (NAD 1983), then your outSR will be 3418. transformForward is for geographic/datum transformations between two GCS.
    – mkennedy
    Mar 7, 2014 at 23:10
  • @mkennedy Sorry I must say that I am new at this. How can I verify my service is using 4326? I regularly project my map points from my map to latlong using this service, doesn't that mean that service is using 3418? How could I assign that to 4269? Mar 8, 2014 at 2:46
  • You might like to look into proj4js to do client-side transforms. See github.com/proj4js/proj4js.
    – ca0v
    Mar 8, 2014 at 14:15

1 Answer 1


You shouldn't need to specify transformForward. Just set the inSR to 4269 (from Geographic Coordinate Systems, for GCS_North_American_1983), and the outSR parameter to 3418.


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