idea Shrink Lines — GP Tool in ArcGIS Pro Ideas

Shrink Lines — GP Tool

Bud — Thu, 23 Mar 2023 06:13:49 GMT

It would be helpful if there were an OOTB geoprocessing tool for shrinking lines at each end. By a measure or a percentage.

It would also be good if the tool could stretch out lines too -- using the angle of the last segment at each end. Or make that separate GP tool.

Thanks.

Related: Batch shrink lines at each end

Re: Shrink Lines Geoprocessing Tool

DanLee — Mon, 20 Mar 2023 17:32:15 GMT

Just want to make sure you are aware of Trim Line and Extend Line tools:

https://pro.arcgis.com/en/pro-app/latest/tool-reference/editing/trim-line.htm

https://pro.arcgis.com/en/pro-app/latest/tool-reference/editing/extend-line.htm

Re: Shrink Lines Geoprocessing Tool

Bud — Mon, 20 Mar 2023 18:29:33 GMT

@DanLee Thanks.

As far as I can tell, the Trim Line tool can't be used to shrink lines -- when dangles aren't involved.

Re: Shrink Lines Geoprocessing Tool

DanLee — Mon, 20 Mar 2023 18:22:56 GMT

Not directly, you are right. You might have to find a way to generate a crossing line at where you need to trim to. Then select both the line you need to trim and the crossing line to use Trim Line tool.

Re: Shrink and Stretch Lines GP Tools

DanLee — Mon, 20 Mar 2023 23:58:56 GMT

I am a bit curious about why you need to shorten the line in both ends. Do you mind describing what you need to do?

Just a thought for a potential workflow: if you have the line(s) selected, you can do the following:

- Use Feature Vertices To Points tool with Both_ends option to obtain the endpoints of the line(s).

- Use Butter tool to buffer the points with the distance that you want to shorten the line at both ends.

- Use Erase tool to erase the lines by the buffer polygons; your lines are shortened.

Would that work? 🙂

Re: Shrink and Stretch Lines — GP Tools

Bud — Tue, 21 Mar 2023 15:56:40 GMT

@DanLee

Here's my current use case, although there are others:

For each road line, I want to count the number of right-of-way polygons that the line intersects (using the Spatial Join geoprocessing tool). The relationship should always be 1 line to 1 polygon. So if the spatial join count isn't 1, then that area needs to be investigated.

The problem is, the roads often slightly overlap other polygons at road intersections, since the polygons aren't snapped to the road endpoints. And automatic snapping isn't an option in scenarios like these: screenshot. So the spatial join will count polygons that I don't care about.

So I figure, if I shorten the lines at each end in a copy FC, either by a measure or by a percentage, then that will avoid counting polygons that just barely overlap the roads.

What do you think?

For my notes, in general, I can think of a few scenarios I need to check for:

1 polygon intersects many lines
1 line intersects many polygons
Lines that don't intersect any polygons
Polygons that don't intersect any lines
The line ROAD_ID matches the polygon ROAD_ID, but the line and polygon features don't intersect -- indicating a possible problem with the ROAD_ID.

Regarding the potential workflow you provided. I will check it out. Thanks!

Re: Shrink and Stretch Lines — GP Tools

DanLee — Tue, 21 Mar 2023 14:42:53 GMT

Note: this comment has been edited to clarify some details and to switch red box #1 and #2 to match Bud's notation change. - Dan

Perhaps you can use Feature Vertices To Points with Midpoint option to obtain midpoint of each line. Then use Spatial Join to join polygons with the midpoints using "Contains" option. For your scenarios:

1 polygon intersects many lines: Look for polygons with Joint_Count >1 (your red box #1)
1 line intersects many polygons: Look for polygons with Joint_Count = 0, (two of the three polygons in your red box #2 would not contain the midpoints)
Lines that don't intersect any polygons: this needs Spatial Join of the midpoints of lines with polygons, then look for Joint_Count = 0. Could there be any line with midpoint is not inside any polygon but the line still intersects a polygon?
Polygons that don't intersect any lines: This may need Spatial Join of the polygons with line using the "Crossed by the outline of" option (I didn't test this, so not 100% sure).

With these processes, you may not need to shorten your lines?

Re: Shrink and Stretch Lines — GP Tools

DanLee — Tue, 21 Mar 2023 14:44:19 GMT

No problem. See my "Note" at top of my comment above.

Re: Shrink and Stretch Lines — GP Tools

SeanLim — Wed, 22 Mar 2023 15:46:25 GMT

Hi @Bud,

I've created a script tool for you that shrinks lines at both ends by a percentage or length.

You can add it to your project from Pro by navigating to the ArcGIS Online tab under Catalog > Portal and searching for "Shrink Line". Note that you have to be logged into ArcGIS Online for this.

Alternatively, you can access it here: https://arcg.is/9H8S8

Please let me know if you have any questions or feedback. Thanks!

Re: Shrink and Stretch Lines — GP Tools

DanLee — Wed, 22 Mar 2023 17:25:38 GMT

Hey @Bud,

Sean Lim who posted the script tool, Shrink Line, above is my teammate. He had some account conflict issue to resolve; that's why there is no Esri badge next to his name. If you are still interested in this tool, please give it a try and let Sean know if it is helpful to solving your problem. Thanks. - Dan

Re: Shrink Lines — GP Tool

Bud — Thu, 23 Mar 2023 06:36:56 GMT

Thanks @SeanLim!

Just a heads up:
I had a rare case where one of the features in my FC had a null geometry. And that caused an error in the tool.

(mobile GDB; ArcGIS Pro 3.1)

But that's an uncommon scenario. It might not be worth worrying about.

Still testing.

Re: Shrink Lines — GP Tool

Bud — Thu, 23 Mar 2023 07:13:51 GMT

@SeanLim

Just a heads up:
There seems to be a quirk where the Use Percentage parameter is mandatory -- even though leaving it unchecked is a valid scenario.

But I can work around it by enabling that parameter, then disabling it.

Re: Shrink Lines — GP Tool

Bud — Thu, 23 Mar 2023 13:11:45 GMT

Hi @SeanLim, I haven't been able to get the percentage option working. The lines in the output feature class don't get shrunk -- they're just copies of the original lines.

But if I use the measurement option, then that works well.

Here's a video:

(view in My Videos)

Thoughts? Thanks!

Edit:
Never mind. I see now that the percentage needs to be a decimal like 0.3. Not 30 percent.
Using .3 works as expected:

Re: Shrink Lines — GP Tool

SeanLim — Thu, 23 Mar 2023 18:07:55 GMT

Hi @Bud, thanks for the great feedback. I've reworked the tool according to your feedback, here are some new things:

The tool will now skip lines that have <Null> lengths. It won't throw any more errors for <Null>s.
The Method parameter replaced the Use Percentage parameter so that you can choose between Percentage and Length. It defaults to Percentage.
Some rearranging of the parameters and some safeguards were added to prevent errors.

For more information on how each parameter works, you can hover your cursor over the parameters to read the tooltips. Let me know if you have any questions/feedback.

Updated tool: https://arcg.is/9H8S8

Re: Shrink Lines — GP Tool

Bud — Thu, 23 Mar 2023 20:36:15 GMT

@SeanLim The new version looks good! Thanks.

Regarding the Percentage/Length parameters: Out of curiosity, if the parameters are optional, then why is the default value of 0 necessary?
And have you considered making those parameters mandatory? I don't have a strong opinion either way, just curious what the thought is behind those parameters.

Re: Shrink Lines — GP Tool

SeanLim — Thu, 23 Mar 2023 21:19:33 GMT

@BudI put the default value as 0 so that the user is less likely to run the tool without an input causing an error.

The parameters are Optional since they can't both be Required (since picking one over the other in Method hides the other one and the user wouldn't be able to fill out the other hidden parameter--which would cause an error).

Edit: if there's anything you would like me to add that would make the tool more convenient for your use, please let me know.

Re: Shrink Lines — GP Tool

Bud — Thu, 23 Mar 2023 22:55:30 GMT

@SeanLim

Regarding the Percentage parameter:
I know you have a tooltip explaining that parameter. But I wonder if a more descriptive name would help avoid confusion. Instead of labeling that parameter as "Percentage", what if you called it "Percentage (as decimal)", or something like that?

Also, I wonder if this blurb in the Percentage tooltip could be clarified:

This value will determine the percentage to shrink the line. Values range from 0.0 to 1.0. The percentage will be applied to the entire length of the line, then the length will be halved and removed from each end of the line.

Maybe some thing like this?

This value will determine the percentage to shrink the line. Values range from 0.0 to 1.0. The percentage will be applied to the entire length of the line — half at each end of the line.

Re: Shrink Lines — GP Tool

DanLee — Thu, 23 Mar 2023 23:24:06 GMT

Hi Bud,

I have suggested to Sean to label that parameter with "Percentage (%)" and accept values between 0 and 100 instead of decimal number. You are right that 0 as a default doesn't make sense; so we will change it to 1 percent as the default. @SeanLim will give you a updated version soon.

We also would like to know if this tool solves your problem. Hope you can comment on that too. Thanks.

Re: Shrink Lines — GP Tool

SeanLim — Fri, 24 Mar 2023 16:37:08 GMT

@Bud

I have updated the following to the tool:

Percentage now takes numbers from 0.0 - 100.0 (Double).
If the tool is ran with an empty Percentage/Length input, a warning will be added after the tool is ran.
A negative Length value will throw an error.
Length and Percentage default to 10

Re: Shrink Lines — GP Tool

Bud — Wed, 29 Mar 2023 21:28:15 GMT

Hi @SeanLim and @DanLee,

I tested the tool and it is working well.

The tool has solved my problem. Thanks!