topic Re: Define Front of a House in ArcGIS CityEngine Questions

Define Front of a House

CharalamposApostolou — Mon, 28 Nov 2011 08:37:34 GMT

How can i define which side of the lot is the front? For example if i am on a corner how can i define which will be the front side?

Re: Define Front of a House

MatthiasBuehler1 — Wed, 30 Nov 2011 09:05:47 GMT

hi .. are you working on imported shapes / footprints ? I guess so, right ?

Re: Define Front of a House

CharalamposApostolou — Fri, 16 Mar 2012 16:20:53 GMT

Hi. Yes. I found how. Thanks. I defined it according to the road side.

Re: Define Front of a House

LucasSaliba_Santos — Thu, 28 Jun 2012 23:50:01 GMT

hi folks,

Well and if I'm working with imported shapes?... what should I do so it recognizes the street side of the lot?
and if I have corner lot, would it recognizes the both street sides as front sides?

thanks... 😉

Re: Define Front of a House

MatthiasBuehler1 — Tue, 03 Jul 2012 08:57:23 GMT

Hi !

Since there's no connection possible in CityEngine between Static Shapes (imported) and dynamic streets, the street orientation must be 'manually'.

There's 2 ways :

1]
select each Street Edge by double clicking it > Shapes Menu > Set Street Edges

2]
use my Python script I made some time ago which does that automatically, though that needs CityEngine Advanced. I'll try to find that script again.

Re: Define Front of a House

MatthiasBuehler1 — Tue, 03 Jul 2012 09:18:24 GMT

hi !

here's the script I made some time ago for this thread on the old forum http://forums.esri.com/CityEngine/forum-40181.html

read the description how to use it.

Re: Define Front of a House

MatthiasBuehler1 — Tue, 03 Jul 2012 10:47:39 GMT

here's a little screenshot of a result :

the fat line being the first edge.

Re: Define Front of a House

LoringTupper — Wed, 20 Mar 2013 21:32:28 GMT

I've got land parcels in an ESRI Geodatabase polygon layer that I'm trying to genereate models from. The polygons have landuse designation on them and that's about all the attribution there is. The plan is to write CGA rules for each land use and apply it to parcel based on the land use attribute value. That part works but in order to do anything that requires knowing the front/side or back of the shape it appears it needs to know where the street is. I have a road network, also from a geodatabase, but there is no connection between the parcel shape layer and the road network layer. From what I can tell geodatabase layers are not static shapes in CityEngine and the Python scripts you have suggested in this thread that will identify the "street side" of a shape apparently only work with static shapes, is that correct? If so, is there any way for me to indicate what the street side is for my parcels of land shapes that are coming from an ESRI geodatabase? This problem has brought our development to a stand still becuase to develope land use CGA rules we need to take into consideration setback for the front sides and back if parcels and we can't tell where the front is.

Re: Define Front of a House

MatthiasBuehler1 — Thu, 21 Mar 2013 11:05:25 GMT

Hi,

Incoming polylines from a GDB are always used together with the 'Dynamic City Layouts', with the Block generation deactivated. ( No subdivisions ).
Incoming polygons are 'Static Shapes' and there is no connection to the 'Dynamic City Layouts' system.

Note that when you select a 'Lot' shape, that you have streetWidth() attributes in the Object Attributes. Together with the First Edge, this is defined by the 'DCL' system.
Now if you just import Static Shapes, it depends where the First Edge is. The First Edge defines 'FRONT' in CGA. Thus, my 2 scripts 'inform' Static Shapes on 1] where the best position would be for the First Edge and 2] where the Street Edges are. This is calculated for selected GRAPH segments.

So since the 'DCL' inform the Dynamic Shapes automatically, we mimic this via Python, to inform Static Shapes.

Additionally, the following issue may also occur to your workflow :
http://forums.arcgis.com/threads/79729-Origin-of-shapes-imported-from-FGDB-seems-arbitrary

NOTE :
The streetWidth() attributes are not standard attributes. They're actually an array ( a list ). That list is just displayed in the Object Attributes as if they were separate attributes. That type of array CAN NOT be ported via GDB directly. Assuming you preprocess your Static Shapes in ArcGIS / FME instead of using my scripts, by addressing both the clockwise issue ( other thread ) and the actual position of streetEdges, the best thing you can do is nevertheless write single streetWidth attributes in ArcGIS per edge and then in CityEngine just create a script which takes those attributes, deletes them and writes an attr array, which then is usable in CGA.

Read this a couple of times, then let me know if questions remain. 😮 Sadly, there's currently no easier way to port this information.

Let me know if you're good in scripting, then I may give you more inputs ! 🙂

Matt

Re: Define Front of a House

LoringTupper — Mon, 08 Apr 2013 19:04:39 GMT

Thanks for the reply Matthias, unfortunately I know very much about CGA so I'll just tell you what I gleaned from your response and what I have read in the notes in the pythion scripts.

1) GDB layers are in fact Static Shapes.
2) I'm to run both of the scripts, first alignStaticShapesToDynamicStreet_v1.py to align the parcel shapes to the street segments, then the SetStreetEdge.py script to identify the street edge of the parcel.
3) the SetStreetEdge.py script creates a streetWidth "attribute" in the parcel layer shapes, this helps identify the street edge of the shape, i.e. the edge of the parcel shape that faces the nearest street line.

Questions:
1) Do I need to select all of the parcel polygon shapes and the street network lines when I run these python scripts?
2) How can I tell these scripts are running and/or completed? I see no indication that anything is happening when I run the scripts with all street network lines and parcel shapes selected. I also don't see a streetWidth "attribute" in the parcel shape object attributes list after running the scripts so I assume they did nothing.
3) If I were to get this to work, i.e. get the streetWidth attribute on the parcel shapes, is there anything I need do in the CGA script assigned to the parcel shapes when I'm assigning setbacks?

Re: Define Front of a House

MatthiasBuehler1 — Tue, 09 Apr 2013 10:48:26 GMT

Hi !

Questions:
1) Do I need to select all of the parcel polygon shapes and the street network lines when I run these python scripts?
2) How can I tell these scripts are running and/or completed? I see no indication that anything is happening when I run the scripts with all street network lines and parcel shapes selected. I also don't see a streetWidth "attribute" in the parcel shape object attributes list after running the scripts so I assume they did nothing.
3) If I were to get this to work, i.e. get the streetWidth attribute on the parcel shapes, is there anything I need do in the CGA script assigned to the parcel shapes when I'm assigning setbacks?

1]
You need to select the shapes you want to 'inform', plus the street segments. ( ONLY the segments, no additional shapes of the streets or blocks. You need that specific selection because I do not clean the selections before running the script.

Note that the script is intended to inform 'footprints', not 'parcels'. Of course you can select any shape, but the script evaluates first ONE street on which it works with, it does not take into account multiple possible streets. That's a limitation of the script.

2]
At the end of the script, a fat line is printed in the Python console, so open the console and check when it appears :

print ("________________________________________")

3]
By running the scripts, the shapes are informed in a manner that CGA will operate correctly.
- The first script, which sets the first edge to the correct 'best street' will make sure CGA's 'front' is aligned there ( along the FirstEdge).
- Once the streetWidth array is written (after running script 2), which defines which edge is facing the same 'best street', CGA will be able to define setbacks based on street.front selectors ( actually doing setbacks away from that street ).

Play with 1 street segment and a few different shapes footprints first to get a grasp how the script runs, and check the setting values on top of the script. There's also a short explanation.

Ok ?

Re: Define Front of a House

LoringTupper — Mon, 15 Apr 2013 16:01:42 GMT

Sorry its taken so long to get back, I got caught up on other matters.
I did manage to get the python scripts to work correctly and was able to apply setbacks to front, back and sides for my properties. I found that I needed to run the "Simplify" tool on the layer in ArcGIS prior to going in to the CityEngine project and applying the python scripts, but it did work for 99% of the parcels I was testing.
Thank you for all of your help with this, I think I can now move forward with my project.

Re: Define Front of a House

MatthiasBuehler1 — Tue, 16 Apr 2013 10:16:06 GMT

Very cool to hear this works in almost all cases.

Bravo !

Matt

Re: Define Front of a House

ErnestoCarreras3 — Thu, 28 Apr 2016 14:53:29 GMT

Hi, will this script assist identifying the front of a house?

Re: Define Front of a House

AidaAfrooz — Sun, 27 Nov 2016 23:33:35 GMT

HI Matthias,

I downloaded your python script but am not sure how to use it. I ran it once through console (not sure if that's the correct way of running it) but nothing happened.

Python> run script is inactive. I checked tutorial 10 but still can't figure it out. Any suggestions?

I would like to automatically detect the street frontage for static shapes which are imported from GIS.

Thanks,

Aida