Converting turn restriction shapefile to turn feature class

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05-24-2018 09:22 AM
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New Contributor

I have a turn restrictions shapefile acquired from a municipality that I would like to use when I create a network dataset. I found these instructions from ESRI to do exactly this: http://desktop.arcgis.com/en/arcmap/10.5/extensions/network-analyst/migrating-a-turn-table-to-a-shap...

However, after converting the shapefile into a feature class and attempting to use the "turn table to turn feature class" tool, the file format is not accepted (.dbf) and yet the syntax provided here: http://desktop.arcgis.com/en/arcmap/latest/tools/network-analyst-toolbox/turn-table-to-turn-feature-... shows .dbf as an acceptable format. 

I have no idea how to proceed from here. I have attached the dataset I am working with along with this post. 

Is there another way to convert my data?

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Esri Regular Contributor

Chris,

The documentation for the Turn Table To Turn Feature class tool states that:

 Converts an ArcView turn table or ArcInfo Workstation coverage turn table to an ArcGIS turn feature class

The file you have, turn_restrictions_mtm3, does not appear to be a valid ArcInfo or ArcView turn table. That is why the tool is not accepting that table.

What system did that file come from? Perhaps it was converted into a shape file format from some other system and not really started as files used for network analysis in ArcView.

Jay Sandhu

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New Contributor

Hello Jay,

The shapefile came from a municipal open data catalogue that you can check out yourself here: City of Toronto - Open Data

It is an ESRI shapefile. If you look into the attribute table of the data it is "street" data just in a different setup than a turn feature and as per the readme, it is used for routing. I'm just trying to figure out a way to facilitate that. 

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Esri Regular Contributor

Chris,

I understand that the format of the file is a shape file. But that in itself is not enough to make it "routeable".

Do you have the street centerlines on which you will be doing the routing? The enclosed centerline_flow shape file in that location is not a connected street network and cannot be used for routing.

 

Drawing the contents of the turn shape file in ArcMap, it seems to draw all turns at an intersection and the turns are offset from the centerlines. ArcView 3x, workstation ArcInfo or the newer ArcGIS does not represent turns in this format. Looking at the attributes of the turn_restrictions_mtm3 shape file, it has a column called MI_PRINX. That indicates to me that it perhaps originated from a MapInfo system. You will have to understand how it represented the turn information. For example, there are a lot of turns with the TURN_IMPED set to -1. Does it mean that turn is not allowed? In which case almost all movement would be restricted. Or does it mean that the turn does not impact routing?

So it is possible that you could do some transformations on the input data to make it amenable to our turn table conversion tool, you will still need a useful centerline file for the actual routing.

Jay Sandhu

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New Contributor

Hi Jay, I should have mentioned, I do have a current centerline to use with this data. It is currently setup with elevation, speed and one way streets. So if I load everything I do have a complete view of all road data.  

To address your question as per "TURN_IMPED set to -1", to my understanding that would prohibit a turn from being made. 

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Esri Regular Contributor

Chris,

This is very old information: The Arcview format for the a turn table (.dbf) at a minimum needs three columns called Node_, F_Edge and T_Edge. Similarly the workstation ArcInfo turn table (.info) format had Node#, FromArc#, ToArc#.

You can rename the columns CENTRELINE to F_Edge and CENTRELI_1 to T_Edge (or you can add new fields and copy values to them). But I am not sure where you will get valid Node id's that were part of the AV network analyst shape file (Nodes.dbf) for the GP tool to disambiguate the  from/to edge ids and come up with a valid turn. There is an INTERSECTI column in the turn table and perhaps that can be put to some use. For example, you can try to make a network on your shape file centerlines. This will create a junction's feature class with junction ids. You can then try to match the junction id's to the INTERSECTI field (maybe a spatial join may work). I would suggest doing this for turns at one intersection and see if you can make it work.

Jay Sandhu