topic How To Use Attribute Rules to Calculate Geometry of Polylines in ArcGIS Pro Questions

How To Use Attribute Rules to Calculate Geometry of Polylines

BenWagner3 — Mon, 31 Oct 2022 21:25:33 GMT

Hello,

I am creating Attribute Rules for some feature classes. I have been able to successfully create rules to calculate the X & Y of my point feature classes, but I have some polyline feature classes that need some geometry calculations performed. I need to be have an attribute rule(s) that would calculate the X & Y of both the start of the line and the end of the line. This rule would run on Insert and Update. I have four attribute fields (Upstream X, Upstream Y, Downstream X, & Downstream Y).

Thanks in advance for any assistance.

-Ben

Re: How To Use Attribute Rules to Calculate Geometry of Polylines

JohannesLindner — Tue, 01 Nov 2022 08:03:03 GMT

// Calculation attribute rule on the line fc // triggers: Insert, Update // Field: empty // get the $feature's geometry var geom = Geometry($feature) // null geometry -> abort if(geom == null) { return } // get start and end point var p_start = geom.paths[0][0] var p_end = geom.paths[-1][-1] // return the x and y values of those points return { "result": {"attributes": { "UpstreamX": p_start.x, "UpstreamY": p_start.y, "DownstreamX": p_end.x, "DownstreamY": p_end.y }} }

Re: How To Use Attribute Rules to Calculate Geometry of Polylines

BenWagner3 — Tue, 01 Nov 2022 20:28:54 GMT

Johannes,

When trying your expression, the expression validates fine, but when saving the attribute rule I get an Error 002941 "An expected Field was not found or could not be retrieved properly." The attribute field names match exact with my feature class attribute fields.

I've attached a screenshot.

Thanks

Re: How To Use Attribute Rules to Calculate Geometry of Polylines

JohannesLindner — Wed, 02 Nov 2022 07:21:04 GMT

First thing that comes to mind: You have to use the actual field names, not the aliases. If you have spaces in lines 15-18, you're using aliases.

If that doesn't solve it, please post your code and a screenshot of the field view of your feature class.