[OSM-talk] Suggestion: fallback tag

Tobias Knerr osm at tobias-knerr.de
Thu Dec 17 19:16:49 GMT 2009


Steve Bennett wrote:
> Solution: tag it like this:
> landuse=reserve
> fallback:leisure=park

Lets assume that your fallback tag isn't just a less specific type of
object than the real tag (in that case, a tag hierarchy - as it is used
with amenity=parking + parking=*, for example - would solve the problem).

In this situation, a fallback is based on certain assumptions how
renderers display a tag. It only works in your example because you make
the assumption that parks are rendered as a green area or something like
that, and that would be appropriate for reserves, too. But some other
renderer might write "park" all over the area or do something else that
makes the rendering completely inappropriate for the feature. What if I
use "beach" as the fallback for my golf bunkers and get ice cone and
beach ball icons, rather than the yellow area I had expected?

Another problem with your approach is that it only works in renderers
designed with the intention to display /everything/. I'd expect good
rendering styles to be limited to a selected subset of the available
information.

Tobias Knerr




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