Geographic Information Systems Stack Exchange is a question and answer site for cartographers, geographers and GIS professionals. Join them; it only takes a minute:

Sign up
Here's how it works:
  1. Anybody can ask a question
  2. Anybody can answer
  3. The best answers are voted up and rise to the top

I've been looking to use the Ordanance Survey's Meridian data (part of the their OpenData suite) for doing vehicle routing.

Whilst I can infer road class from the NUMBER property on each polyline, I cannot see anything that indicates if a polyline is unidirectional, or bidrectional. Am I just being unable to see this, or is this encoded somewhere else?

share|improve this question
I suspect that OS reserved that information to a paid product. – iant Sep 7 '10 at 20:06
up vote 1 down vote accepted

Major Issue with Meridian 2 Data from Ordnance Survey (in OpenData format):

Motorways, major and minor roads are represented in the data. Complex junctions are collapsed to single nodes and multi-carriageways to single links. To avoid congestion, some minor roads and cul-de-sacs less than 200 m are not represented in the minor road feature description of the data. Private roads and tracks are not present.

Stated here

You can BUILD a Road Network (ArcGIS Network Analysis does an okay job)

But if you want full Network (Road Transport) capabilities you will be require at cost

Integrated Transport Network (ITN) Road Restriction Information (RRI) ITN RRI

share|improve this answer
Looking at that user guide, even the paid-for Meridian data wouldn't include it. Hadn't seen the ITN data, and might fit on a project that I'm working on for a client. – Rowland Shaw Sep 8 '10 at 8:32
ITN is Expensive and not based on Tiles but Area. ITN with RRI is even more expensive. You might find TeleAtlas or Navteq data more fitting for you project at lower cost. – Mapperz Sep 8 '10 at 14:40

Your Answer


By posting your answer, you agree to the privacy policy and terms of service.

Not the answer you're looking for? Browse other questions tagged or ask your own question.