topic Re: Intermodal Network Construction in ArcGIS Network Analyst Questions

Intermodal Network Construction

BenKeller2 — Wed, 19 Dec 2012 14:40:14 GMT

I am creating an intermodal network for North America, and have rail, road, intermodal facilities, and nodes for both rail and road. I made sure my connectivity was correct so that the facilities were connected to both rail and road. As of right now my only parameters, that were made by the too not me, are miles and oneway. Are there any others that I should be creating or is that sufficient to start. Unfortunately I do not have a turn class, but my main analysis is basically visualizing where rail cars are leaving the network to travel on road, and where they are returning to rail. Also, I do not need to snap my intermodal facilities to line segments correct? Obviously most facilities span a large distance and are not directly on top of the rail or road. Any extra help or insight would be great.
Here is the intermodal network I am currently using minus the waterways:

http://cta.ornl.gov/transnet/Intermodal_Network.html

Thanks,
Ben

Re: Intermodal Network Construction

BenKeller2 — Wed, 19 Dec 2012 18:19:46 GMT

I ended up creating the network dataset as is, but the problem is that my facilities that allow travel between rail and road are not connected to edges of the network. I have around 1200 points so manually connecting them with lines is not an option. Also they each are specified as either one way terminal or two way terminals, meaning you could go from rail to road, road to rail, or both. Any help with setting a parameter for this would be amazing, I am assuming I would have to rebuild my network though.

Thanks
Ben

Re: Intermodal Network Construction

RamB — Sun, 06 Jan 2013 13:43:54 GMT

I propose the following:

Assuming, intermodal facilities are point features. Use the "nearest" tool on intermodal facility, once each for rail and road. Later combine this table, such that you have a point feature table that has facility ID, road node ID (nearest to facility) , rail node ID (nearest to facility). Get coordinates of these three sets of nodes.

Following the procedure on this page, prepare a text file to create lines. Later use the "ascii/ text to feature tool" to create your connections (i would call them dummy, as they dont exist in reality)

You next question on one-ways and two ways is no different than those in network analyst tutorial for multimodal networks. When you read tram in the tutorial think about it as rail 🙂

regards,

Re: Intermodal Network Construction

BenKeller2 — Mon, 07 Jan 2013 12:14:42 GMT

Thank you very much! I am working with the near tool, and ArcMap crashes sometimes, but that might be because I have too much data. Do I have to rebuild my network dataset to establish the "dummy lines" as connections?

Re: Intermodal Network Construction

BenKeller2 — Mon, 07 Jan 2013 13:53:39 GMT

I have the lines created, but there is no node at the end points of my line segments, so it still thinks there is no connection

Re: Intermodal Network Construction

RamB — Mon, 07 Jan 2013 14:25:36 GMT

Yes, you must have nodes. Without nodes you cannot have dummy lines, so that surprises me. In case you do not have nodes, but you somehow (strangely) have the dummy lines, use planarize tool to break your highway line segments at the point that they would intersect with dummy lines. Do the same on the other side to railways lines.

Once you have nodes on highways and railways and for the facilities, you must rebuild your network.

regards,

Re: Intermodal Network Construction

RamB — Mon, 07 Jan 2013 14:27:06 GMT

I am assuming you have basic knowledge of building networks in Arcgis, if not, please try the tutorials first. it will help you a great deal.

kind regards,

Re: Intermodal Network Construction

BenKeller2 — Tue, 08 Jan 2013 13:45:46 GMT

I restarted, so now I have the original point, other data, and both rail and road coordinates. I want to create the lines as you said, but from the text file is difficult because I have over two thousand points and to edit the text file into that vertical format will be very time consuming. There is no way to create a line from the original point to other XY coordinates in an attribute table? That seems very simple but yet I have not found it.

Re: Intermodal Network Construction

BenKeller2 — Tue, 08 Jan 2013 17:03:34 GMT

This is what I have....

Re: Intermodal Network Construction

JaySandhu — Tue, 08 Jan 2013 19:50:59 GMT

Have you looked at the GP tool XY to Line?
http://resources.arcgis.com/en/help/main/10.1/index.html#//0017000000tv000000

Jay Sandhu

Re: Intermodal Network Construction

RamB — Wed, 09 Jan 2013 02:08:25 GMT

Jay has given a good solution. i personally transfer the table to excel and write macros. Sure it cannot be a manual process 🙂
Ask around your workplace, I am sure there should be a few people who write macros in excel.

regards,

Re: Intermodal Network Construction

BenKeller2 — Wed, 09 Jan 2013 13:17:09 GMT

Thanks a lot for you help along the way here! I ended up doing some geoprocessing and created some new ID fields and a master field and made multiple XY event layers and appended them together followed by the point to line tool with my sort field. I have it all built now with my facility nodes snapped to rail and road and the connectivity set to both rail and road, and the nodes set to override. When I create a test route it still says there is no route between the two? Do I need to create a node for both rail and road classes at the intersection of the transfer edges as well? I will try that out as my next step!

Re: Intermodal Network Construction

BenKeller2 — Wed, 09 Jan 2013 13:17:54 GMT

oops forgot my attachment.....

Re: Intermodal Network Construction

RamB — Wed, 09 Jan 2013 15:56:32 GMT

Yes, you are going in the right direction 🙂 . You need nodes, then define their connectivity while building the network.

regards,

Re: Intermodal Network Construction

BenKeller2 — Wed, 09 Jan 2013 17:13:29 GMT

So I got it to work but not correctly. When I test to see if it travels across modes I just select a point on each side of the transfer lines on road and rail. The problem is it routes across the entire country to another facility and then all the way back to the second point. I think it is doing this because the facility actually connects to the end of a rail segment. I have checked my connectivity and made sure my points are snapped also. I am not sure what to look at now. Good news it that it is at least connecting between both modes, bad news is that it is only at one facility.

Re: Intermodal Network Construction

RamB — Thu, 10 Jan 2013 03:28:05 GMT

This is because of end-point connectivity and because your lines are not split where they should be. Solution, split lines where ever is necessary eg., at points where you think rail wagons switch lines (criss-cross) similarly with roads.

I do not understand your third picture. the route does not seem to be using the transfer link

Re: Intermodal Network Construction

BenKeller2 — Mon, 14 Jan 2013 11:48:07 GMT

All three pictures are of the same route. The third picture is just the two points I used to test the connection and it rerouted across the map. I will check my connections again, and I made sure to use the Split Line at Intersection tool. They should be split but checking again does not hurt.

Thank You

Re: Intermodal Network Construction

BenKeller2 — Mon, 14 Jan 2013 15:01:04 GMT

For some reason the Split Line at Point tool does not split all the rail segments at the point where the transfer edges meet the rail edge. Only some of them have a vertex created, and others are off by a meter or less and obviously the connection is not made at those nodes.

Re: Intermodal Network Construction

BenKeller2 — Tue, 15 Jan 2013 12:09:16 GMT

After measuring how far off the break is from the point, at 1:1 scale, it is literally inches. I understand it probably is just an error in the split line at point tool because it is so minimal especially at the large scale I typically work at. Any suggestions as to how to fix it?

Re: Intermodal Network Construction

BenKeller2 — Tue, 15 Jan 2013 18:48:36 GMT

Does ArcCatalog reproject all the data after it builds the network dataset? I am confused as to how some vertices where I split at the point are no longer coinciding and some are? I have repeated the steps again, and the same thing happened.