points accesibility test help ¡¡¡¡

For my PhD thesis I´m making a connectivity / accesibility test of a certain urban area streets.

i have a problem with the accesibility test, cause i need to know wich points of the grids have direct connections with the others, as the image example

Any idea, to how finally get a list with all the points and their direct accesibility correspondence?????

Thanks ¡¡¡¡¡¡¡¡¡¡¡

Ps: here are the 3dm & Gh files

PhD_Connectivity_Test.3dm

PhD_Connectivity_Test.gh

Replies to This Discussion

Permalink Reply by Mario L on January 3, 2013 at 11:53am

are you any good at writing your own C# nodes? because I think of a few ways to do this but it would require some custom code.

how soon do you need this?

Permalink Reply by jorge sainz de aja on January 3, 2013 at 12:05pm

i have some basic notions of scripting in C#, but i tried and didn´t worked ;(

Permalink Reply by newy011 on January 3, 2013 at 12:02pm

Why cant 7 also connect with 6? Why cant 1 connect with 2? Why cant 11 connect with 7???

With such little information and no logic, Mario i really would love to see you script Something! If you can be that nonsensical and get a PHD, i might do one myself!

Jorge can you elaborate, or have you had too many late nights!

Permalink Reply by jorge sainz de aja on January 3, 2013 at 12:10pm

7 is connected with 6 but need to pass through 5, so its not directly connected

the accesibility matrix test the accesibility of nodal points through the direct connections between two streets

Permalink Reply by newy011 on January 3, 2013 at 12:16pm

How would you describe that programatically then? ie, in c#? You would have to write quite a ridiculous set of rules for it to know that. What about if these points change? If 6 is in-line with five (and in-between 5 & 9) then what happens. There are just too many unknowns for this to be solved with such a simple explanation. Your problem is easy for a brain to know, but difficult for a computer to understand. Think about a CAPTCHA, i would say its the equivalent problem: we can decipher what one says almost immediately, but a computer can not.

http://en.wikipedia.org/wiki/CAPTCHA

Or have i not under stood you correctly?

(Also, just to start with the problems that need to be addressed, lets go back to why 1 and 2 are not connected? 2 & 3 are, 3 & 4 are etc. Its already inconsistent. You need to define rules. You've mentioned nothing about proximity, which as far as i can decipher, seems to be a driving factor behind what you have pointed out. Its all very confused to be honest)

Permalink Reply by jorge sainz de aja on January 3, 2013 at 12:30pm

Yes, you understand correctly

changing connecting lines would result in a change in the final results in the connectivity matrix, and then a change in the values of arrendable land price. there are examples of previous studies (william alonso 1964).

The script should be easy at first (could be a simple Boolean test) but my knowledge is limited in script, and I have no time to learn as I'd really like c # or python

Permalink Reply by newy011 on January 3, 2013 at 12:42pm

I have some c# experience, enough to script something to 'begin' to solve this but your talking a lot of hours work to do something which between person to person is very simple to understand. Heres the first problem:

1. Define 7 as the start point.

2. Iterate through the remaining list of points, find the closest point

3. Now, what do you do: find the next closest point from the previous one? Or stick testing from point 7? Note that if you stick with 7, how do you then deal with NOT creating a line between 6? (Or put another way, what will tell the computer its found all the shortest paths and to begin testing from the next set?) If you test each path as the alternative, you will end up with a diagram completely different to what you have drawn in numerous solutions, in fact, they would just be incorrect, not without an exhaustive and overly complex set of conditionals.

You could define zones - circular extents - but that again will produce results differently to what you have drawn, namely connections such as 2 & 3, 2 & 8, 3 & 4, and of course 1 & 2 would be problematic with this approach. Do you see why this isn't as simple to solve using a computer?

Mario, here's your moment....(i hope youre still young, it might take some time, and it needs to work for any possible combination, not just the one above! I'll pass)

Permalink Reply by jorge sainz de aja on January 3, 2013 at 12:34pm

the lines are given by a real street map, so........................, 1 & 2 are not connected

simply like that

Permalink Reply by Chris Hanley on January 3, 2013 at 12:31pm