Multiple Curve Intersections and Selections

Hello.

I have two shape files that are imported as polyline curves. What i ultimately need to do is select from the First Set (property lots) all of the curves that intesect the second set (Zoning Districts). This will tell me which properties within the set exist in more than one zone.

I've gotten this far, but cant seem to get a set of all the property lines that are crossed by zoning lines. From using GIS, I know the answer should contain 28 properties.

I've attached what I've done so far, any help would be appreciated.

Attachments:

Multiple Curves Intersection.gh, 61 KB

Replies to This Discussion

Permalink Reply by Joseph Oster on January 13, 2016 at 12:39pm

Your file has no data to work with. Can you internalize the output from the two 'ReadShapefile' components? Connect each of them to a 'Geo' param, right click on the 'Geo' and 'Internalize data'.

Permalink Reply by Eric Galipo on January 13, 2016 at 12:51pm

Sorry About that. I had internalized the data, but didn't use a GEOMETRY component..

Thanks for taking a look at this.

Attachments:

Multiple Curves Intersection - INTERNAL.gh, 4 MB

Permalink Reply by Joseph Oster on January 14, 2016 at 10:40am

I've been kicking this around... Thought I had 28 results at one point but it slipped away as I explored different options. I began to suspect the data so added a 'Visualize' group to see the property lots as extrusions with their height depending on perimeter length. Then I added a 'Cull Duplicates' group to avoid properties that had duplicate 'Area' centroid points. That reduced the number of properties from 364 down to 331, though five of those have 'Area' values between 88 and 205, ten have values less than 500 while the average is ~1.3 million!

So the data is still suspect. Some appear to be nested inside of others? But using those 331 properties, I now find 32 that intersect the 'Zoning Districts'. But that's not the same as a list of properties that span two or more 'Zoning Districts'... Not having fun anymore. :)

Permalink Reply by Joseph Oster on January 14, 2016 at 11:15am

Minor code re-org to reduce wait time when opening file with "Visualize" group disabled. Now get 31 results, not 32...

Attachments:

MultipleCurvesIntersection_2016_Jan14c.gh, 4 MB

Permalink Reply by Eric Galipo on January 15, 2016 at 3:03pm

Wow. Thanks for all the time you put in on this, sorry it was becomming less fun. However, I may be able to help you out a bit.

In the "property lots" shapefile there is a data field called "split zone" which is an indicator of which ones are considered to exist in more than one zone. (i added a list item) to the internalized data so you can see them. So you can use this to KNOW exactly which 28 lots actually need to be analyzed against the "zoning boundaries", and which are considered to be completely contained.

The trick here (and what I do not know how to do). Is to perform an operation on ONLY the lots that have the "Y" flag in the "Split Zone".

Essentially what i need to do is to calculate the PROPORTION of the LOT that exists in each of the ZONES, but the tree/list needs to stay in order because i have to match those proportions back up at a later point.

You've already done so much already, but if you could take a look and maybe even get me started (like. How do i perform an operation ONLY on geometry that has the "Y" indicator?) that would be super helpful.

Thanks!

Attachments:

Multiple Curves Intersection - INTERNAL V2.gh, 4 MB

Permalink Reply by Joseph Oster on January 14, 2016 at 6:21pm

The three smallest in my list of 31 "property lots" have a total area between them of only ~522 square units - less than 1/5th the size of the next larger property on the list. If these three small anomalies(?) are ignored (filtered), that leaves 28.

Attachments: