[OSM-talk] Tag combinations: amenity and highway

[Peter Wendorff]

Am 13.06.2012 14:19, schrieb john whelan:
> I wonder about lumping things together sometimes.  Locally we have gas 
> stations amenity=fuel that have a convenience store and a ABM or ATM 
> in OSM language.  I'm tempted to have three separate POIs in much the 
> same way as a bank with an ATM have two POIs together.
I would prefer distinct POIs, too, but I doubt that the problem is 
exactly what you claim it to be:
> The problem with putting too much information on one POI is the 
> rendering systems have problems with more complex coding especially 
> how do you display it?  Even to distinguish between a bus_stop and a 
> bus_stop with shelter in a simple way with different icons doesn't 
> seem to be standardized.
The complex coding is one issue, but how is it solved now?
Let's consider one POI with complex tagging. Renderers usually would 
have more than one matching rule for it, e.g. a bus-stop icon, an icon 
for a waste-basket and a third icon for the shelter.
Most renderers will select either one of them or all three of them to 
render, and in the latter case two of the three will be omitted because 
there's not enough space to render all three.

The alternative would be three distinct POI with one of the attributes each.
In the bus-stop example let the waste-basket be mounted to the bus-stop 
pole and the pole being one corner of the shelter: All three are very 
close together.
A renderer matches all three rules again - now one for each POI, and 
often will omit again two of three corresponding icons (here two of 
three objects) because of space collisions.

But other problems occur:
- A bus stop has a size of often 10x3 Meters - nevertheless it's 
generalized to one node in OSM usually; and that's often okay.
- I'm working for blind people, so being able to describe where in the 
bus-stop area the waste-basket or the bench is, is a benefit for my 
application: left or right of the shelter?

A renderer might generate collection-icons for nearby objects, but it's 
not possible to do it the other way around.

regards
Peter
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