[OSM-talk] The Return of the Highway tags and other junk

[guy at graviles-reynolds.org]

Quoting Dirk-Lüder Kreie <osm-list at deelkar.net>:

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> Ben Robbins schrieb:
> We are creating maps. Maps are abstracted from the real world. I
> understand that we are currently debating the level of abstraction. In
> my opinion everything you try to achive by adding these complex entities
> can be achieved by a reasonably connected and tagged node.
> And like Andy Allan said, if someone else has to update your data, he
> won't know why you placed your nodes the way they are and will probably
> unknowingly destroy what you have fine-tuned.
> 

I have to agree with Andy and Dirk here, as you could by not staying with the 
agreed tagging structures find that work hard work is destroyed either by 
someone indadvertantly deleating it as they updated the map or by an automated 
filter purging the dataset of unreognised tags. 

I also agree with Dirk that we are mapping the the planet so that it can be 
navigated not making a scale drawing so that we can recreate it. Thus we 
compromise and use easily recognisable symbols to represent features, and not 
first angle projections of them.

Coming back to gates and cattle grids, these cannot be represented by anything 
else but a node if they are to be used by navigation software reading the way 
as they exist as the intersection of two features such as a fence crossing a 
road. Thus if the fence crosses a road with a cattle grid and you make the 
cattle grid the correct width and in the fence the road won't see it and vice 
versa, either that or you ahve to have a single node at the crossing point as 
you do now with four short segments radiating from it each with the 
tag "cattle_grid=yes". Having the node as a cattle grid making the intersetion 
between the fence and the road you have the quickest and simplest method of 
recording and rendering it. Similarly with gates, stiles, fords and any other 
obstacle that results from a crossing point they need to be recorded as nodes.

When recording gates and cattle grids in features that run parallel to roads 
you will obviously have to create a short track off the road and then place the 
gate/grid node on that rather than on the road itself.

Guy