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After posting this I realised I had forgotten to mention that I am working off downloaded NZ road shapefile from - so perhaps this download does not include all road attributes. I also noted a New Zealand discussion on highway attribution - so I will follow up with the New Zealand OSM group.

In New Zealand there is a clear distinction between roads that are state highways and roads that are not. They are managed and signposted separately. Although open street map data has a variety of entries in the 'name', 'ref' and 'type' fields, it is not possible to create a valid query just for state highways. This is primarily a problem of consistency in attribute usage.

I would like a simple query to be able to select all New Zealand state highways and think that many users of the data would find this useful. I am aware that different countries have very different hierarchies for roads and different administrative and management classification systems.

My simple suggestion would be to add a new type to the roads layer = 'NZ State Highway', and apply this to all state highway road sections in New Zealand. Is this a reasonable approach? How could this be done better? How could this be made more generic to be useful to the wider community? Should another attribute be added to roads? Should the new type just be 'Highway' - even though this means different things in different countries?

Examples of state highway attribute data existing currently.
1. where 'name' like "SH" "State Highway" "SH36" "Highway"
2. where 'ref' like "SH" - in practise either "SH2" or just "2" has been used
3. where 'type" in ('motorway', 'primary','trunk') - although this usage is not consistent - some state highways are classified as 'secondary' and not all 'primary' roads are state highways

This question is marked "community wiki".

asked 12 Jul '11, 05:26

Filby's gravatar image

accept rate: 0%

edited 12 Jul '11, 06:35

In OpenStreetMap, the highway (not type) tag is used to indicate a road's prominence in the country's road system.

There are certain internationally agreed values for this tag: highway=motorway, highway=trunk, highway=primary, highway=secondary, highway=tertiary, highway=unclassified, and highway=residential.

Different countries have their own rules for what type of road gets what value, and often (though not always) these coincide with administrative classifications. In the UK, for example, "primary A roads" with green signs are tagged highway=trunk; other A roads with black-and-white signs are tagged highway=primary; and B roads are tagged highway=secondary. You can read a country-by-country list of these rules on the wiki.

New Zealand doesn't appear to have settled on a consistent set of rules yet. It would be good if it did. You can discuss this on the local mailing list, but you should be aiming to agree on a rule whereby "all state highways are classed as highway=trunk, and the ref tag just contains the number" or something like that.

permanent link

answered 12 Jul '11, 08:10

Richard's gravatar image

Richard ♦
accept rate: 18%

edited 12 Jul '11, 10:35

Jonathan%20Bennett's gravatar image

Jonathan Ben...


Additionally you may want to set operator="NZ state highway agency" or similar. But again that has to be decided by the New Zealand community and this help site is the wrong forum to do so.

(12 Jul '11, 09:39) petschge

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question asked: 12 Jul '11, 05:26

question was seen: 4,690 times

last updated: 12 Jul '11, 10:35

NOTICE: is no longer in use from 1st March 2024. Please use the OpenStreetMap Community Forum