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Hello guys, I often make the motorways or expressways open, and here is my question: what for should I have highway=construction if I already have construction=motorway which is already a highway? It looks as if I put 2 tags: highway=construction and construction=highway, which is self-understanding that they are equal. It just fills OSM with additional memory and so it loads computers too much. Thank you

asked 18 Jul '16, 05:53

Ukraroad's gravatar image

accept rate: 0%

In OSM, "highway" means "any road, street or path" - the meaning is specified by highway=motorway, or highway=-residential, or even highway=footway. Construction is designated by highway=construction , with construction= specifying the type of construction. "construction=highway" does not add any extra info on what is being constructed; "construction=motorway" does.

I think you might be confused by the "motorway" meaning of the word "highway" - in OSM, highway is a keyword, not a road type.

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answered 18 Jul '16, 07:53

Piskvor's gravatar image

accept rate: 37%

edited 18 Jul '16, 08:06


As an example, consider "residential" - that's valid both as a highway type and as a landuse - "landuse=construction; construction=residential" is different to "highway=construction; construction=residential".

(18 Jul '16, 08:03) SomeoneElse ♦

The wiki article ( also does a fairly good job of explaining why both tags are needed.

(18 Jul '16, 09:47) Lightsider

The tagging combination also makes it a lot easier to disseminate when rendering if you've ever tried to use QGIS to create a map using OSM data.

(19 Jul '16, 02:31) Longhorn256

I did not mean I am confused that motorway is the same as highway, I just don't understand why don't just put construction=motorway

(21 Jul '16, 05:11) Ukraroad

For a data consumer, what is described by an object with only the tag "construction=motorway"? Is it a highway? Is it an area of land where a motorway is being constructed (ie. "landuse=construction")? Is it something else? That tag alone doesn't sufficiently describe what the object is. Using "highway=construction" clearly indicates that it's a highway under construction, and the "construction=motorway" tag expands on that by stating that the type of highway under construction is a motorway.

(21 Jul '16, 16:46) alester

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question asked: 18 Jul '16, 05:53

question was seen: 2,637 times

last updated: 21 Jul '16, 16:46

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