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 |
One Answer:
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 I think you might be confused by the "motorway" meaning of the word "highway" - in OSM, answered 18 Jul '16, 07:53  Piskvor 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".
The wiki article (wiki.openstreetmap.org/wiki/Key:construction) also does a fairly good job of explaining why both tags are needed.
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.
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
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.