Range Fan Calculator: Can you calculate and pass a processing coordinate system WKID instead of making it static?

Question

ArcGIS GeoEvent Server's Range Fan Calculator Processor creates a range fan output polygon for each input point. One of its parameters is the Processing Coordinate System WKID. The documentation says the default value is 3857 (Web Mercator), but the documentation also says to choose a "WKID appropriate to the area or extent of the processed event records" with an example of using a South Carolina state plane WKID if your data is in South Carolina.

Suppose I want a GeoEvent service that can make range fans for a variety of regions, too many to add a separate processor for each. And suppose there is a way to determine an appropriate processing coordinate system (for example, use the Intersector Processor with input points and a state plane zones feature layer). Is there a way to pass the desired coordinate system's WKID to the Range Fan Calculator Processor each time it runs? Or am I stuck with a default like 3857 and living with the distortion?

RJSunderman · Accepted Answer

Hey Gary --

I checked and the Processing Coordinate System WKID parameter is expecting a literal integer value. This particular processor is not set-up to handle dynamic substitution, so we cannot extract a WKID value from another attribute field to make the processor more dynamic with regard to spatial reference. I've added your use case as an enhancement for this processor, but cannot commit to a timeline for which the enhancement will be picked up for any particular release.

For now, if data you receive spans a wide geographic area and you need to create a buffer or calculate a range fan, you will have to select and specify an integer WKID for a projection generally applicable across a wide area of operations. Since a projection like Web Mercator is "generally inaccurate everywhere", perhaps you can identify a "zone" in which the data resides and choose a projection more or less in the middle of that zone. That way, at least, you would not be working with 250+ highly accurate projections for specific areas within a U.S. State (since you mentioned the State Plane Coordinate System). If you select one projection for the "Pacific NorthWest" and another for the "Atlantic SouthEast" perhaps your range fans will be accurate enough -- at least more so than using a world-wide Web Mercator projection.

-- RJ