Meerkat GIS Street Offset - trim/cull intersecting curves

Hello,

I am reading curves from a SHP file using Meerkat in Grasshopper. The curves are placed where streets are placed. I have offset in both the positive and negative direction in order to get correct width of the street.

My question is how do I remove the intersecting curves. My first thought was to use a pattern cull and then reference the base street curve as the culling pattern, and then the remainder of the curves as the list component.

Red: base curve

Green: offset curves

Is there an easier way to accomplish this?

Thank you,

Forrest Walker Whitmore

Attachments:

Intersecting_Curves.JPG, 62 KB

Replies to This Discussion

Permalink Reply by Jeremy Jih on June 13, 2015 at 5:21am

Hey Arend, I'm trying to RUnion several sets together, but the operation always seems to mess up and miss many interior curves. I'm not very knowledgeable about data trees; could you tell me what I'm doing wrong here?

Permalink Reply by nikos tzar on June 13, 2015 at 5:43am

Hi Jeremy,

It's really hard for anyone to say what's wrong without being able to look inside your file...

One thing I can notice by the image, is in clipper you don't need to provide the negative offset value as well. With one value you get both sides offset.

Permalink Reply by Jeremy Jih on June 13, 2015 at 5:55am

Hey Nikos,

Of course--sorry, I had meant to attach the file. And thanks for telling me about the negative offset value. Here's the file--thanks!

Attachments:

ming beijing plans.3dm, 891 KB
streets offset.gh, 37 KB

Permalink Reply by nikos tzar on June 13, 2015 at 8:04am

that seems hard...

The problem is that you are missing the "Holes" outputs from all the offset components.

In theory, you could graft all the inputs of the offset components (offset each line separately) and then use [region union] and get the desired result.

In practice, booleans are quite buggy and the above doesn't work as expected...

I am sorry, I can't think of a working solution for this at the moment... hopefully someone else could help...

Permalink Reply by Jeremy Jih on June 13, 2015 at 8:14am

Hey Nikos,

No worries, I knew it might come to this--booleans are always a thorn in my side...buggy bastards, haha. I'll keep futzing around, and failing that I'm sure I can come up with a brute force option to do by hand. Thanks for your input!

Permalink Reply by nikos tzar on June 13, 2015 at 8:19am

this is the best I have come up with, maybe you can take it from there...

(it uses polyboolean from clipper again. Most crossroads are ok but it still messes up a few...)

Attachments: