Tag Info

Hot answers tagged

19

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 ...


17

Creating great circles could give you the desired effect. Maybe something like discussed on http://lists.osgeo.org/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( ST_Segmentize( ...


13

[Edit: this has been superseded by nx_spatial which is available from pypi (easy_install nx_spatial).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

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 ...


11

Similar to the graph suggestions by @Adam Matan there is a tool called Flow Map Layout that will create a tree like visual of data. Perhaps you can use something like that. http://graphics.stanford.edu/papers/flow_map_layout/


11

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 ...


10

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 ...


10

Although the thread is a bit old, I wanted to add a few links about routing in case someone ends here like I did: OSRM <- Recommended Routino


9

I found a couple of good examples lately and figured would update the thread with these pretty cool examples A recent article in the open journal PLoS, Redrawing the Map of Great Britain from a Network of Human Interactions by: Carlo Ratti, Stanislav Sobolevsky, Francesco Calabrese, Clio Andris, Jonathan Reades, Mauro Martino, Rob Claxton, Steven H. ...


9

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 ...


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 ...


8

The short answer is that there isn't one especially if you're looking for a TransCAD or Emme/2 alternative as there is no open source package that comes close to those. The closest you can get are some micro modelling solutions like Transims or matsim that I find lacking of a lot of needed data, methodologies, tools, or network handling that are available ...


7

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 ...


7

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 ...


7

See this help document for creating multiple connections. This simple code will create multiple connections: EXEC SQL CONNECT TO testdb1 AS con1 USER testuser; EXEC SQL CONNECT TO testdb2 AS con2 USER testuser; EXEC SQL CONNECT TO testdb3 AS con3 USER testuser; You can then choose a connection to use: EXEC SQL AT connection-name SELECT ...


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

Have a look at this paper: From spatial interaction data to spatial interaction information? Geovisualisation and spatial structures of migration from the 2001 UK census, by Alasdair Rae


6

This paper by Koichi Yagi shows how the accelerometer in a smart phone can be used to measure roughness. Update Whatever software you end up using, I think it needs the ability to manage road condition surveys. An important role of pavement management is prioritizing road repairs and deciding when to re-surface instead of repair. I'd like the road in ...


6

I'll try to analyze your use cases from a QGIS perspective: Software that allows me to drive a specific route and store that as a working model. There is a GPS Tool for live tracking of GPS devices. But I guess you could go with the simpler version of loading the recorded GPX files into QGIS after collection. Download some GPS/County information to ...


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

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, ...


6

You can use Schematics - The ArcGIS Schematics extension provides a sophisticated data model and a comprehensive set of tools for creating, managing, analyzing, and displaying complex networks. Perhaps less well known is the fact that it contains tools to create custom schematic layouts. You can use ArcGIS Schematics to create maps for any linear network ...


5

Firstly, am I correct that the image shows a polygon to point relationship? If so you want to make sure that the polygons stand out more and should visually match the links. I would suggest choosing a group color (say blue), use light blue polygon fill, a dark blue border (helps the eye resolve the edge of the polygon) and medium blue for the link ...


5

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 ...


5

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.


5

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


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 ...


5

We are working on a multimodal routing for Austria (also for pedestrians). What I can say till now: You need the data: It took at least 4 years and even longer to collect all the necessary walkways, barriers, steps, opening times, streets, railways, bikeways, ferrys, and, and and...and its still going on You need a router which can interprete theses graphs ...


4

If you're looking for a programatic pythonic solution, take a look at networkx


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 :)



Only top voted, non community-wiki answers of a minimum length are eligible