topic Re: Snapping points to linear features... in Geoprocessing Questions

Snapping points to linear features...

MarkEnglish — Thu, 05 Aug 2010 16:34:00 GMT

Is there a tool or multiple tools that would assist me in snapping multiple points to the closest linear feature, which in turn will be used for linear referencing. Thanks in advance for any help!

Re: Snapping points to linear features...

DanLee — Fri, 06 Aug 2010 17:04:52 GMT

One idea you can try - it is not snapping but creating points at the nearest locations on the lines:
- Run the Near tool on your points, with the "Location" option. This will add the NEAR_X and NEAR_Y fields to the point input.
- Then run the Make XY Event Layer tool, using the point feature class as the XY Table and the NEAR_X and NEAR_Y fields as the X and Y Fields. This should give you a point layer with all the points on the lines that are nearest to the input points.
- You can run Copy Features to save this layer to a feature class; all the input point attributes are carried over.

Hope the spatial associations of your points with lines are clear. If any point is in the same shortest distance to more than one line, then you might get a point on the wrong line.

Thanks.

Re: Snapping points to linear features...

MarkEnglish — Wed, 11 Aug 2010 21:22:58 GMT

Thanks a lot Dan. Your right, I will have to verify accuracy by using detailed quality control. Thanks again...

Re: Snapping points to linear features...

DanLee — Wed, 11 Aug 2010 21:48:49 GMT

You are welcome. I am glad it helped. Good luck.

Re: Snapping points to linear features...

MarkEnglish — Tue, 21 Sep 2010 15:34:09 GMT

Hi Dan:
Is there a method of accomplishing this task by using topology? Just a thought.
Thanks!

Re: Snapping points to linear features...

DanLee — Tue, 21 Sep 2010 22:00:39 GMT

Are you thinking the topology rule for points - "must be covered by" lines? It might give you the association between points and lines, but doesn't snap or move your points to the nearest lines. I think these are two different things.

Re: Snapping points to linear features...

MarkEnglish — Wed, 22 Sep 2010 22:04:21 GMT

OK, I was just toying with another approach. Unfortunately, it moves the arc feature as well. I found the best approach to be your first suggestion of using the Near tool. Thanks again...

Re: Snapping points to linear features...

DanLee — Wed, 22 Sep 2010 22:13:13 GMT

I am glad to hear that. Yeah, it's good to test different ideas; just be aware that some tools with fuzzy tolerance or snapping options may alter the input locations. Make sure you understand the tools you are using. 🙂

Thanks for letting me know.

Re: Snapping points to linear features...

MarkEnglish — Thu, 23 Sep 2010 16:05:36 GMT

Hey Dan! Are you guys hiring in the Geoprocessing Department? I can shoot you my resume if applicable... Thanks!

Re: Snapping points to linear features...

DanLee — Thu, 23 Sep 2010 16:28:34 GMT

Mark,

I appreciate your interest, but this is not the right place to discuss such matter. You are welcome to post your resume at our website - career:
http://www.esri.com/careers/index.html

Thanks for understanding.

Re: Snapping points to linear features...

AlejandroMata — Tue, 31 Jan 2012 19:25:13 GMT

Are you thinking the topology rule for points - "must be covered by" lines? It might give you the association between points and lines, but doesn't snap or move your points to the nearest lines. I think these are two different things.

Hi Dan !

I want to make virtual lines to connect a point layer to a line layer, and i want that these lines are included in the lines layer.

As the image shown below.

[ATTACH=CONFIG]11578[/ATTACH]

I was trying to make a topology with the rule " Point must be covered by lines ", it select all the points but i dont know how to create the lines to connect between the layers. Do you have some suggestion ?

Thanks in advance.

Re: Snapping points to linear features...

DanLee — Tue, 31 Jan 2012 20:44:00 GMT

Once you have the POINT_X and POINT_Y of points and the NEAR_X and NEAR_Y in the same table (as I decribed in the beginning), you can use the XY To Line tool with the default Line Type - Geodesic, if you have ArcGIS 10. This tool creates a line using the two point coordinates in each row of your table.

Please be aware that the line created by this tool is a geodetic line - a curving line along the surface of the earth - not a planar line; and it is densified with many vertices. Theoretically there is a difference in length between the geodesic line and the planar line between two points, but at this level of detail, that difference is ignorable. You may also use the Generalize tool (Editing toolbox, Editor license) with a reasonable tolerance to remove the unwanted vertices, so that your lines become two-point straight lines. To avoid mis-use of this tool, we might consider developing a different tool in the future for creating planar lines between two points.

Re: Snapping points to linear features...

AlejandroMata — Wed, 01 Feb 2012 13:56:14 GMT

1812;168209 wrote:
Once you have the POINT_X and POINT_Y of points and the NEAR_X and NEAR_Y in the same table (as I decribed in the beginning), you can use the XY To Line tool with the default Line Type - Geodesic, if you have ArcGIS 10. This tool creates a line using the two point coordinates in each row of your table.

Hi Dan !

Im using ArcGis 9.3, if i dont have ArcGis 10, what can i do ?

Greetings !

Re: Snapping points to linear features...

DanLee — Wed, 01 Feb 2012 16:01:13 GMT

This tool was part of the previous Military Analyst extension in 9.3. If you don't have that, can you write a python script to read the coordinates and write out line features? If you don't know how, you can try to post your question on the Python Forum; someone might already have the code to help you. I am afraid I don't have the time to work on this now.