topic Re: Why when I divide or split a polygon one of the resulting parts disappears in ArcGIS Pro Questions

Why when I divide or split a polygon one of the resulting parts disappears

SaraRamos — Wed, 24 Jun 2020 07:51:10 GMT

I have different polygos and I need to divide them because they actually correspond to 2 different houses. However, when I draw the line to divide the polygon one of the resulting parts just disappears. Could you please guide how to avoid this and just to get two new polygons with its corresponding area (the rest attributes should remain the same)

Re: Why when I divide or split a polygon one of the resulting parts disappears

LarryMasters — Wed, 24 Jun 2020 13:35:21 GMT

Is your symbology set to where it disappears upon the split?

Re: Why when I divide or split a polygon one of the resulting parts disappears

Till_Schmid — Wed, 24 Jun 2020 14:18:17 GMT

Hi Sara Ramos

Thanks for your question.

Could you specify your issue a little more? For example, does this problem occur only with this specific parcel/polygon or as well in other cases? Did you originally load your parcels using the Data Manager (cogwheel button in the upper right of the map overview) or did you draw the polygon yourself directly in the Plan editor?

Thank you in advance for the additional information,

Till

Re: Why when I divide or split a polygon one of the resulting parts disappears

JoeBorgione — Wed, 24 Jun 2020 14:20:13 GMT

As Larry Masters‌ suggests, is your original house layer symbology controlled by a definition query? I bet I've done that 100 times: create a new feature but it does not appear. The new polygon will not have the field value you have your definition query set, hence it can't be shown on the screen.

Here I define just those points with the value of T in the Status field be shown:

If I were to add a new point, it would not appear until I update its Status Field to equal 'T'

Re: Why when I divide or split a polygon one of the resulting parts disappears

SaraRamos — Thu, 25 Jun 2020 12:26:30 GMT

Hello Till

Thanks a lot for your reply. The problem occurs with all the polygons that

I try to divide (split). The polygons that I have come from a

digital image, which I classified (using the classification wizard of

ArcGIS Pro) and the transforming the classified image (raster) into

polygons. Let me show you an screenshot, with the polygons that I got to

represent the houses:

I read that the split tool responds to "domain split policies", i do not

know if the problem is because of those policies, but I can not figure out

what happens with one of the parts of the polygon that is cut.

Thank you very much!

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Re: Why when I divide or split a polygon one of the resulting parts disappears

Till_Schmid — Thu, 25 Jun 2020 12:53:46 GMT

Hi Sara Ramos‌

It seems that you are trying to split Polygons in ArcGIS Pro. Therefore I moved your question from the ArcGIS Urban community to ArcGIS Pro and hope, that the experts there are able to help you.

Please do not hesitate to reach out again, if you have any questions about ArcGIS Urban.

Till

Re: Why when I divide or split a polygon one of the resulting parts disappears

LarryMasters — Thu, 25 Jun 2020 13:00:31 GMT

When you spit them, have you tried to select or identify them (click where the missing house should be). That would tell you if the symbology is hiding it or not. Also possibly in attribute table to see if a new one was generated.

Re: Why when I divide or split a polygon one of the resulting parts disappears

Scott_Harris — Thu, 25 Jun 2020 16:32:38 GMT

Hi Sara,

Based on your screenshot, the symbology does not include "all other values" as a class:

Your screenshot:

Here is where you can change it:

My best guess is when you split the polygons, they are getting null values or another value for the Class_name attribute. If the Class_name field is a domain, you will want to check in the Domain view what the split policy is:

If it needs to duplicate when you split, choose Duplicate.

Does that help?

-Scott

Re: Why when I divide or split a polygon one of the resulting parts disappears

SaraRamos — Thu, 02 Jul 2020 10:20:48 GMT

Dear Larry, thank you so much for the help. I tried to select the polygon

that I can not see anymore after the split, but it is not there something

to select. On the other hand,. here there are two screenshots of before and

after the split. after I split it seems that a second feature is created,

with the same ID.

Before:

After I split:

Can you notice that although the left part of the polygon is selected,

there is not a polygon itself? therefore, once I clear the selection the

polygon on the left is just gone.I tried also to include "all other values"

in the symbology but it did not work.

Thanks a lot and I hope we can find out what is happening.

Best regards,

Sara

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Re: Why when I divide or split a polygon one of the resulting parts disappears

SaraRamos — Thu, 02 Jul 2020 10:25:00 GMT

Dear Scott,

I included the "all other values as a class", but nothing changed. Also, I

modified the split policy in the Domain, as you can see in the following

screenshot, but the problem remains.

And I have followed recommendations given in this discussion but still can

not solve the issue

Do you have any other suggestions? Thank you so much for your help!

Best regards,

Sara

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Re: Why when I divide or split a polygon one of the resulting parts disappears

SaraRamos — Thu, 02 Jul 2020 10:27:25 GMT

Dear Joe, thanks a lot for your reply. I have read but I actually do not

have clear what is the purpose of the queries, could you please let me know

about it a bit more? I tried some query but it did not work.

Thank you so much!!

Sara Ramos

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Re: Why when I divide or split a polygon one of the resulting parts disappears

JoeBorgione — Thu, 02 Jul 2020 13:00:45 GMT

Sara Ramos‌ A defintion query allows you to view only those features that meet a certain criteria. For example, in the county in which I work there are roughly 450,000 parcels. Each one of them has a 'City' field populated with the name of the respective city the parcel is within. Instead of drawing al 450,000, parcels, I can make a defintion query just to show those parcels where City = 'Emigration Cyn'.

Re: Why when I divide or split a polygon one of the resulting parts disappears

Scott_Harris — Thu, 02 Jul 2020 15:12:25 GMT

Hi Sara,

Does the field you are symbolizing on, Class_name, have a domain applied? You can check in the Fields view (right-click on the layer > Design > Fields).

If not, then my theory about the domain split policy causing this might be incorrect. If I were you, I would experiment with the Symbology of the layer - perhaps change it to Single Symbol instead of what you currently have.

If you can't figure it out - please consider contacting Esri Technical Support

Thanks,

Scott

Re: Why when I divide or split a polygon one of the resulting parts disappears

AnnaSvátková — Sun, 30 Jan 2022 21:44:25 GMT

Hello,

I've had the exact same problem, the layer created in ArcGIS Pro; mine was created from a selection of another layer. I lost some data this way and had to get them from the backup. I merged the layer with the lost part from the backup via Merge in Geoprocessing, which created new, combined layer, which was saved in the Geodatabase. The new layer finally allowed me to split polygons and keep both parts, probably because this time the source was saved in the GDB and not just in the table of contents. Hope this helps somebody 🙂

Re: Why when I divide or split a polygon one of the resulting parts disappears

JohannaKraus2 — Mon, 30 Jan 2023 18:49:49 GMT

Hi - I'm running into this situation with a polygon footprint layer that is hosted on agol and being editing in PRO. I don't have a definition query and it's not the cartography. Did anyone discover anything?

Re: Why when I divide or split a polygon one of the resulting parts disappears

Starc_Industries — Fri, 08 Sep 2023 15:19:18 GMT

Same problem here. In my case, it also seemed to the result of me creating from a selection of another layer. In another attempt, I created the new layer using the "Copy Features" geoprocessing tool. When I attempted the split on this new layer, both halves of the split polygon were retained.

Re: Why when I divide or split a polygon one of the resulting parts disappears

KeithFeickert — Mon, 23 Mar 2026 21:58:43 GMT

This issue occurs when using a layer created from a selection. By exporting this temporary layer to a permanent dataset, you can perform a split without the split area being removed. I believe the error stems from the layer's source still referencing the original parent selection. I hope this helps anyone else facing this, as ArcGIS Pro doesn't provide specific feedback when a split fails to execute as intended.