Hi Viking, Thank you for synthesis and proposal update.
2017-08-20 2:02 GMT+02:00 Viking <vikin...@tin.it>: > > Francois, as a firefighters, I can say that it's very very important to > distinguish a pressurized hydrant from a dry hydrant (or suction point). > And we all agree. > And now I explain the reason why I prefer this distinction in the primary > key. > First of all in many cases you don't know the pressure, but you know only > that it's a pressurized hydrant. You should use something like > fire_hydrant:pressure=positive that adds complexity and it's error prone > for an inexperienced mapper. > I agree with you for fire_hydrant:pressure=positive complexity. water_source=mains or water_source=network may be enough The point isn't to know exact pressure, only source is a concern for us. > Then, for my fire departement, I've extracted hydrants data from OSM, I've > uploaded it on some old and new GPS and I've sent it on my colleagues > smartphones. > The simplest (and in many case the only) way to tranfser hydrants > attributes to GPS is to put them in waypoints names. But waypoints names > lenght is limited in GPS, so it's likely that someone transferring data > will loose the fire_hydrant:pressure information. > Then it's simpler to look for emergency=fire_hydrant or > emergency=suction_point than look for emergency=fire_hydrant + > fire_hydrant:pressure=positive or emergency=fire_hydrant + > fire_hydrant:pressure=suction. > In conclusion grouping different items under the same primary key and, > even worse, grouping all water sources under emergency=water_source, adds a > not necessary complexity in data managament. > Simpler is always better. In this case it is simpler to keep > emergency=fire_hydrant for pressurized hydrants and emergency=suction_point > for all other non pressurized water sources. > I'll follow you on tagging simplicity and stop argue on grouping under emergency=water_supply. If we take this way, it may be really good to add water_source on both emergency=fire_hydrant and emergency=suction_point. Even if an hydrant is always pressurized, it can be fed by a private water grid. Then we have at least 2 sources : mains and private_network (or similar) For sake of simplicity, fire_hydrant: and suction_point namespaces should be avoided as done for fire_hydrant:position Since all hydrants will have emergency=fire_hydrant, some keys can be lightened fire_hydrant:wrench => wrench (and automatically make it available for suction_points also) fire_hydrant:type or suction_point:type => fire_hydrant or suction_point To follow Moritz logic for pillars, pillar=dry_barrel or wet_barrel is enough > For suction point another proposal of refinement is needed. > Not sure on this point if grouping under a single emergency=* value is abandoned. Both features have keys in common. All the best François
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