Hot answers tagged transportation
15
The problem is to figure out how much to bend the arcs to enhance their visual resolution.
Here's one solution (among the many possible). Let's consider all the arcs emanating from a common origin. The arcs get most crowded here. To separate them the best, let's arrange it so they spread out in equally-spaced angles. It's a problem if we draw straight ...
12
[Edit: this has been superseded by nx_spatial which is available from pypi (easy_install nx_spatial). Importing shapefiles is now standard in networkx 1.4]
I've been kind of disappointed by the lack of geometric network tools in ESRI's Python GP API, so I wrote up something that loads Shapefiles and Feature Classes into networkx directional graphs ...
12
Creating great circles could give you the desired effect.
Maybe something like discussed on http://postgis.refractions.net/pipermail/postgis-users/2008-February/018620.html
Update:
I've followed up on this idea in "Visualizing Global Connections". It's a purely PostGIS-based solution using reprojection to create arcs.
SELECT ST_Transform(
...
10
IRIS is one existing open-source solution you should probably be aware of:
From Wikipedia:
IRIS (Intelligent Roadway Information System) is an open-source
Advanced Traffic Management System (ATMS) software project
developed by the Minnesota Department of Transportation. It is used by
transportation agencies to monitor and manage interstate and ...
8
Unfortunately, some of those feature are deeply dependent of the piece of software you use.
For example, let's take the U-Turns in ArcGIS and PGRouting. In ArcGIS, it is something you can choose as an option, in PGRouting, it is nested in the code.
On way street can be processed in two way. The are set up part of the graph with a very high cost ...
7
There is an interesting project from Ilya Boyandin on the go - JFlowMap.
It's not yet publicly available but screenshots look very promising indeed. More info here and here.
You might be also interested in browsing some of the papers about movement geovisualization from Natalia & Gennady Andrienko.
UPDATE: GraphRECAP and FlowMap might also be of ...
6
Here's a draft logical data model I've been told (unofficially) they are working on implementing at Colorado DOT. It is geared for ArcGIS, but I think it is generic enough to borrow parts of for use in PostGIS without having ArcSDE.
It is not clear to me how (or if) this data model fits into the Rome project at Esri.
Update
Also check out Designing ...
6
I also agree this is an interesting problem. Instead of buffering transit lines though, I'd start out with stops, which are part of the Google Transit Feed Specification. RTD's feed is here. Perhaps use GraphServer to build trees.
6
My basic intuition would be displaying the data as a graph, not as a map. Think of it as a subway line map: It does not display the lines on a geographic map, but as abstract lines which intersect on junctions. That way you can focus on the important part (i.e, the next station; how to move from one line to another) instead of being distracted the actual ...
6
When faced with tasks like this your primary objective is to be rational. Don't change params based on 'gut feeling'. While the gut seems to works for Hollywood it does not for us who live in the real world. Well, at least not my gut ;-).
You should:
establish a usable and repeatable metric (like the time required by a pgrouting query)
save metric results ...
5
Disclaimer:
I haven't been up to speed on the research or best practice on this so forgive me if I miss anything and it's been 3 years since I worked with a Travel Demand Model. And when I did travel demand models, I didn't spend a whole lot of time and effort into building turning penalty/restriction models.
Turning restrictions and penalty settings ...
5
OpenFlights Licence is favourable.
"Licensing and disclaimer
The OpenFlights Airport, Airline and Route Databases are made available under the Open Database License. Any rights in individual contents of the database are licensed under the Database Contents License.
Airport data derived OurAirports and DAFIF, as well as route data from Airline Route Mapper, ...
5
Google uses the GTFS (General Transit Feed Specification) standards
https://developers.google.com/transit/gtfs/
The Full List of all the live feeds
http://code.google.com/p/googletransitdatafeed/wiki/PublicFeeds
This is a list of transit schedule data published by transit agencies
and operators in GTFS format for developers to use. They contain
...
4
There's Flowmap, a niche GIS package designed for dealing with network analysis issues.
If you have a fairly simple use-case, the QGIS-based Quantum Navigator might do the trick.
GRASS also supports network analysis, though it may not be worth the friction of getting things set up inside of the environment.
4
The way I read this there are a couple of possibilities: You have cost data for each hour in a 24 hour period; or you have 1,000 nodes which change position every hour across your network. I'm assuming either way that you have the directionality and costs of the network sorted.
In either case you should be able to do this through GRASS. Import the network ...
4
No standard GIS I know of includes such transportation modeling in the core product. So, if you plan to use ArcGIS, QGIS, uDig, etc., you'll need to weave your own implementation. There's an ESRI transportation industry group, and while their web resources will emphasize ArcGIS, many of the approaches and ideas are likely to be useful on other platforms too.
...
4
This is a hard problem that as far as I know is not solved. A look at the current literature (http://scholar.google.com/scholar?hl=en&q=spatial+interaction+data+visualization) seems to support this view. Alisdar Rae has some interesting maps in ...
4
TeleAtlas now TomTom
http://licensing.tomtom.com/OurProducts/TrafficProducts/index.htm
Enterprise Traffic
Navigate with up-to-the minute information
Multinet Coverage Map (PDF)
http://licensing.tomtom.com/OurProducts/MapData/ssLINK/TA_CT048001
4
Include a cell phone technology example.
Maybe mention how police using GIS technology can determine if someone was sending text messages while driving. They can obtain a log of the text messages and a log of positions, then use timestamps to determine speed of the car while text message was sent.
Even if this isn't really possible, tell them it is :)
4
The National Highway Travel Survey collects the trip information you're looking for and can be found here for all the US.
First I would start looking at the FHWA planning data warehouse. If that doesn't help, you have a few options:
Contact the major state and urban DOT / MTO and they'll usually give you the data you're looking for. This option yields the ...
4
I have just the same problem and was about to ask on mailing lists, so thanks to everybody!
I am using Shooting Star with a million and a half rows on the routing table. It takes almost ten seconds to calculate it. With 20k rows it takes almost three seconds. I need Shooting Star because I need the turn restrictions.
Here are some ideas I'm trying to ...
3
I don't know of any tool that will to this out-of-the box. But I'd give it a try with PostGIS.
After loading all four files into the database, you can reference the stops and control points along the corresponding route line geometries using ST_Line_Locate_Point(). This way, you'll have the information necessary to calculate distances between successive ...
3
Maybe the INSPIRE data specification for transport networks could be usefull?
It uses a generic model of networks presented in this document, part 9.9.3.
3
The simple vs complex
This might be overkill for your low-level represtentation
but highlights potential pitfalls with road networks and rules (oneway etc).
All Networks require Topology from simple linked-nodes to complex mathematical algorithms
keeping it simple: see
4.1 Simple link-node networks (point and line)
4.3.1 Translating the link-turn-node ...
3
Geographic Information Framework Data Content Standard, Part 7c: Transportation - Roads
and
INSPIRE Data Specification on Transport Networks – Guidelines
They have some of what you're after but they are really broad. You don't state your use case. Just make sure you don't do more than you need to.
3
We have just created a branch in git for a turn restricted shortest path @
https://github.com/pgRouting/pgrouting/tree/trsp
Sorry no documentation yet, but but if you ask questions on the pgRouting list I hang out there and will respond. This code runs much faster than shooting star and is based on Dijkstra algorithm.
-Steve
3
What about using OpenStreetMap data via the OpenStreetMap Loader for ArcGIS? This white paper from ESRI UK might help as well.
3
We've got that OurAirports data on WeoGeo Market where you can order a small subsection.
http://www.weogeo.com/blog/Data_Blog-World_Airports.html
You could just take this link and place an order for that area of florida and look at what the data provides. It's a pretty good dataset.
2
Assuming you're not looking at spending on something like Oracle, take a look at this PostGIS tutorial on network topology, which discusses building a network topology. Also, you could take a look at PGRouting for PostGIS, which aims to introduce routing functionality to PosGIS.
Alternately you could try GRASS GIS for networking which works quite well.
As ...
2
I tried something similar once (using FME's NetworkCostCalculator).
The interesting part is in the visualization. We wrote the data to 3D PDF, with time as the Z axis, and a background image at certain time intervals.
You just turned on the 10min image, or 15min etc - to show how far you could get in a certain time.
And if you turn the network into ...
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