idea Add flip direction method to Polyline class in Python Ideas

Add flip direction method to Polyline class

DuncanHornby — Sat, 03 Dec 2022 16:57:42 GMT

It would be very useful to add to the Polyline geometry class in arcpy a method that flips the direction of vertices. This could be done in situ or the method generates a new Polyline geometry (my preferred option). ArcObjects allows you to call such a method. Currently one has to program this logic which is tiresome when it seems such an obvious thing that one might want to do to a Polyline, reverse its direction.

Re: Add flip direction method to Polyline class

RPGIS — Mon, 05 Dec 2022 19:33:10 GMT

I believe it already exists. I don't know if this is what you are looking for but here is something akin to it.

Flip Line via Python

Re: Add flip direction method to Polyline class

DuncanHornby — Tue, 06 Dec 2022 11:42:35 GMT

@RPGIS , I am aware of this geo-processing tool, that requires at least a standard license. I'm suggesting that the list of methods on the geometry polyline class be expanded to include a "flip" method. This would allow for cleaner easier coding and would compliment the long list of existing methods and frankly I'm surprised it does not exist already as reversing the direction of a polyline is a very common task. This should not be a task only accessible to higher license level tools.

Re: Add flip direction method to Polyline class

RPGIS — Tue, 06 Dec 2022 12:49:55 GMT

I've ran across something similar, but the way I've handled it was to simply convert the polyline into an array of points and then use the reverse method to basically flip the line and then recreate the original polyline.

That's the only method I can think of that will do that using the geometries.

Re: Add flip direction method to Polyline class

DuncanHornby — Tue, 06 Dec 2022 13:09:58 GMT

That was my solution, but it just seems like overkill to me, having to create new arrays, inserting points in reverse then rebuilding a new polyline. Exposing it as a method of a polyline would make for simpler and cleaner code. It would probably be more efficient too as I understand that arcpy is often a wrapper to some uber fast c++ code.

Re: Add flip direction method to Polyline class

RPGIS — Tue, 06 Dec 2022 17:30:58 GMT

That would be simpler, however you could also do a couple of things to make it easier:

Write a function that reverses the polyline direction
Create a script and write it a class to then be called by any script as a module that can be imported into any script
Make a copy of the python library and modify the geometries portion of the newly copied library to include the line reversal

Aside from those suggestions you would have to see if Esri would be willing to implement your idea.

Re: Add flip direction method to Polyline class - Status changed to: In Product Plan

HannesZiegler — Fri, 16 Aug 2024 11:44:42 GMT

We're working on this! This status does not guarantee that the functionality will be in the next release, but development work has begun. Release cycles vary by product so make sure to check the product life cycle information to get an idea of when to expect the next release.

Re: Add flip direction method to Polyline class - Status changed to: Implemented

HannesZiegler — Fri, 08 Nov 2024 15:55:46 GMT

This idea has been implemented in ArcGIS Pro 3.4, please see the Python section of the What's New in ArcGIS Pro 3.4 topic and scroll to ArcPy.

The Polyline object has a reverseOrientation method to reverse the direction of line features.