[Tagging] power=* tag: minor_line vs. line

Ralph Aytoun ralph.aytoun at ntlworld.com
Wed Oct 14 09:14:48 UTC 2015

Please remember that this is OpenStreetMap and most mappers are not experts on the features they are mapping. It is my personal appeal to all to allow a tagging system that allows general mappers to put a specific feature on the map using overall basic tags and then the experts can come in and “add” additional tags to break it into it’s specific grouping or usage and even take it to the nth degree of ridiculous if they so wish. Let us take the Electricity Grid as that example, if the general mapper can identify a power line on the aerial imagery then they map it as a power=line. They may even have the ability to identify the position of most pylons (if the imagery shows a good shadow to identify between pole and pylon) through open country, it becomes a lot more difficult and blurred in Towns and Cities. For those who have a bit more local knowledge of the grid they may then add the major detail such as National Grid which carries the highest voltage, this breaks down to a lower voltage at a sub station to enter the regional grid and then repeats this step to a lower voltage again for the local or distributer grid. 
Hopefully you will bear in mind the mapper and the process of getting detail on the map before you start deciding that the mappers should all be using the detailed knowledge tags that you are proposing. If the tags get too detailed for general mappers then you are going to stop them from adding basic detail to the map. I for one will stop adding power lines altogether if I do not know if it is high or low voltage, national or local grid. I WILL CONTINUE TO MAP THEM IF I AM ABLE TO JUST TAG IT AS A POWER LINE and be able to leave it up to someone with more knowledge to identify it further.
Please remember the majority of mappers are not experts in all fields. I may identify a structure on the aerial imagery and identify it as a building but I have no way of knowing if it is a family home, a corner shop or a local pub ... so I tag it with the most general tag building=yes. I need to be able to do the same with power lines ... a very basic tag for general use.

From: David Marchal 
Sent: Wednesday, October 14, 2015 8:19 AM
To: Tag discussion, strategy and related tools 
Subject: Re: [Tagging] power=* tag: minor_line vs. line

Well, I would say: mainly on poles = minor_line, and mainly on towers = line; this way, the difference is easy to see for mappers, even on Bing imagery, and, as poles, AFAIK, are always smaller that towers, that would properly model the landscape impact these power lines have. Besides, I know we're not supposed to map for the renderer, but the OSM Mapnik stylesheet seems adapted for such modelling, as minor_line are rendered only on higher zooms, i.e. starting from z16, which seems to me a correct rendering for lines on poles, far less visible than lines on towers. I mean, the stylesheet guys made a logical choice, why not adopting the same? Date: Tue, 13 Oct 2015 22:48:58 +0200 From: fl.infosreseaux at gmail.com To: tagging at openstreetmap.org Subject: Re: [Tagging] power=* tag: minor_line vs. line (Sent from a phone) Hi David, Many opinion exists regarding the minor or not line qualification and still no consensus. As consumers may not be able to make the right distinction between minor or major lines, I assume using power=line only, in continental France and always in combination with voltage=* and operator=*. Thus both users and mappers only have information instead of hypothesis and can make the distinction they want from the voltage, location and operating company. Additionally, underground power paths use to be mapped with power=cable + location=underground Let us know if you have better idea to improve power line mapping ;) All the best François 

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