idea Prevent multi-part features in ArcGIS Pro Ideas

Prevent multi-part features

Bud — Wed, 22 Mar 2023 15:47:42 GMT

Scenario:
Multipart features get created by accident. The person who created the features merged two lines together, but didn't realize that a multipart feature was created.

Or, in some cases, multi-part features get created on purpose. We don't want that either.

There ought to be an optional setting in a feature class's properties for preventing multi-parts from being created. Currently, I don't think that functionality exists.

I imagine it would be possible to disallow multiparts using an attribute rule. But at this point, we've got so many attribute rules in the works that we're terrified that we're creating a monster. We'd much rather there be OOTB functionality for this stuff. (Similarly, we want to prevent true curves via a FC property too.)

Thanks.

Re: Prevent multi-part features

DanLee — Sun, 26 Jun 2022 00:43:20 GMT

Did you use Dissolve tool to merge lines? If so, there is a "Create multipart features" option on the tool which you can uncheck. I am not aware of any other tools that create multipart features, unless you did it manually.

You can use Multipart To Singlepart tool to turn the multipart features into singlepart.

https://pro.arcgis.com/en/pro-app/2.9/tool-reference/data-management/multipart-to-singlepart.htm

Re: Prevent multi-part features

Bud — Mon, 27 Jun 2022 10:01:04 GMT

@DanLee

The multiparts were created manually in an existing FC.

Here's an explanation from a related post:

Multipart features were created manually...by accident. The person who digitized the roads merged two lines together, but didn't realize that a multipart feature was created.

We want to prevent our users from manually creating multipart features.

Re: Prevent multi-part features

JayCary — Mon, 27 Jun 2022 16:14:23 GMT

The Evaluate Part Count check (configured as a constraint attribute rule) will prevent the creation of multi-part features during editing.

Re: Prevent multi-part features

DanLee — Mon, 27 Jun 2022 20:34:56 GMT

Thanks Bud for the request. I have notified our Editing team about this.

As a post-editing option, you can use Calculate Geometry Attributes to calculate "Part Count" to a field. Any feature getting a value greater than 1 would be a multipart feature.

Re: Prevent multi-part features

Bud — Mon, 27 Jun 2022 21:42:30 GMT

@DanLee Thanks Dan. I suspect many organizations face this same problem where multi-part features get accidently created (via manual editing/merging).

And it's occurred to me that some organizations might not realize the problem exists. I imagine there are scenarios where you wouldn't notice the multiparts, unless you had a reason to look for them. Until one day, an issue pops up.

So it's great to hear that the Editing team will be taking a look. Cheers.

Re: Prevent multi-part features

DanLee — Mon, 27 Jun 2022 21:57:14 GMT

You are welcome Bud. Unintended multiparts can cause problems in analysis. Calculate Geometry Attributes (part count option) may be the easiest to detect them; and Multipart To Singlepart tool returns singleparts. I hope people will vote this request up. 🙂

Re: Prevent multi-part features

Bud — Mon, 27 Jun 2022 23:37:07 GMT

Multiparts also cause lots of problems in SQL analysis too (ST_GEOMETRY, SDO_GEOMETRY, or whatever the spatial type is).

Unauthorized multi part polygon

LouisViallet — Thu, 09 Mar 2023 11:36:20 GMT

In ArcGIS Pro or in Portal, it’s happen often that users draw a polygon and do a miss click when they do a double click to terminate the polygon. In this case, we have polygon like a butterfly and it’s create multipart. After that, we need to delete the wrong part by script but we don’t know in all case if it’s a mistake or not.

We need to remove multiparts because we do export of our data to external partner which can’t read multipart.

The idea is to limit multipart directly at the creation rather than do a fix script.

To do that, we can imagine a checkbox to unauthorized multi part in feature class properties.

Re: Prevent multi-part features

LouisViallet — Tue, 14 Mar 2023 14:00:15 GMT

The methods explains by @JayCary works for me.

I have created a constraint rule with :

var rings = Geometry($feature).rings;
return(Count(rings)==1);

There is just a strange behavior on web editing. The polygon is not created, it dissapear without comprehension because there is no message.

Re: Prevent multi-part features

Bud — Wed, 22 Mar 2023 15:50:44 GMT

Multi-part lines will be the end of me. They cause problems every time I try to do something.

Yes, eventually we'll undertake several large projects to get rid of multipart features in all of our FCs. And deal with the fallout in all of our dependent/related FCs and tables. But that will take a lot of time.
And then afterwards, once our organization has fully switched to a modern version of Pro, we'll prevent multiparts going forward using attribute rules. But as mentioned, we'd prefer it if preventing multiparts were an OOTB FC property, not a customization.

In the meantime, multiparts make analysis unnecessarily difficult.