Proposed features/Lines management
|Status:||Draft (under way)|
|Definition:||Qualify power or telecom supports where lines branch, transpose, split or cross|
This proposal is the second one about the tower:type key cleaning.
You may be interested to read more about it
Proposal & rationale
Line management is about the how lines are arranged on a given support. They can branch, cross, split or their wires can transpose.
Here are some definitions in use in power domain, useful to define some terms and values of this proposal
- Branch line (601-02-10) : A side line connected to a main one to feed some consumers hard to reach with main network
- Transposition (466-05-10) : A change in the conductor/bundles configuration of a line. The transposition may be intended to preserve grounding or interference conditions (power/telecom lines)
- Termination (461-10-01) : End part of a line intended to properly ensure safety and insulation on a point of connection on a dedicated support.
OSM currently describes the management of power lines mainly with multi-purpose key tower:type=*. The same key is used to make the difference between a castle and a telecommunication towers based on their structure and material. This is inconsistent and less usable.
This information is useful for telecom wires too. Then it's more appropriate to deal with standard cable management terms and share those concepts without specialised terminology for each domain.
It is proposed to use a new line_management=* key to free tower:type=* and pole:type=* from defining how lines are arranged. This would allows us to keep tower:type=* to define towers shape and to extend line management concepts to other kind of supports like poles, portals or even terminal anchors. Current available tagging describes those situations globally without any specific terminology regarding power nor telecom. This proposal is mainly usable for utilities networks and this work could easily be extended with more specific terms or be used for other fields of knowledge also with further proposals.
Among other things, current tower:type=crossing is used to describe individual towers designed to make lines crossing large obstacles like rivers. As it's not a matter of topology nor proper line management, it's proposed to move it through height=* and design=* which give a better description for such infrastructure.
Simple supports with no particular line management situation aren't supposed to get line_management=* key.
- Share equivalent concepts between many fields of knowledge (power, telco, cable transport / towers, poles, masts, terminal and portals) and provide to mappers a common set of terms matching what they will actually see on the field.
- Ability to describe on the same feature how lines are arranged and simultaneously how they are attached (with line_attachment=* without get stuck on domain specific terminology.
- Split according values to a dedicated key and free tower:type=*, pole:type=* with less related values. Prevent the definition of same kind values to :type keys.
|line_management=branch||A side line going in a different direction connects to a main one on a support.|
|line_management=split||Two or more distinct lines split apart towards different paths. Incoming circuits have to come from the same origin.|
|line_management=transpose||The conductor bundles arrengement changes on a given support|
|line_management=cross||This value indicates there is no connection between two or more lines sharing a given support. It prevents the use of things like connection=no.|
|line_management=loop||A patch is connecting several independent line systems coming from the same direction. This is in use on power systems as to maintain one of them under network voltage for monitoring purpose while disused (no power transit).|
|line_management=termination||A termination implies one or more lines are anchored on a given support with no connection between them.|
Transition supports aren't terminations
It is assumed that a support connecting an underground cable to an overhead line isn't a proper termination for sake of consistency with split and branch definitions.
If such support were terminations, aerial to underground split and branch can't exist and the support should be described with line_management=--no_value_for_straight_line--|termination which is not desirable.
Transition supports souldn't get any line_management=* value.
Let's illustrate this proposal with a concrete usecase summarizing many individual possibilities.
Further thinking is required to address complex situations, as line management can mix several configurations on different tower levels.
Once a little more work will be done on Matrix_values, proposed values for line_management=* could be used together to better reflect situations occuring on the same tower/pole support node.
You'll find below a chart illustrating what you shoud see on ground and how to use corresponding line management values.
- Create line_management=* and add proposed values.
- Edit tower:type=* and remove branch, split, transpose, cross and terminationrelated to power=tower association
- Edit power=terminal and make it implies line_management=termination.
- Edit power=pole and change pole:type according values for line_management=*.
- Edit pole:type=* and warns about possible mistakes with line_management=*
Values to be replaced
|Obsolete tag||Usage volumetry||Used for ?||New tag(s) to use|
|tower:type=branch ( + branch:type=tap)||1721 on 2019-10-15||A side anchored line connect to the main one||line_management=branch|
|tower:type=branch ( + branch:type=split)||2616 on 2019-10-15||Two or more independant circuits continues in different directions||line_management=split|
|tower:type=branch ( + branch:type=cross)||286 on 2019-10-15||Two or more independant circuits share a common support without connection||line_management=crossing|
|tower:type=branch ( + branch:type=loop)||123 on 2019-10-15||Two or more independant circuits are connected in the same direction to maintain a dead part of the network under a positive voltage||line_management=loop|
|tower:type=termination||5017 on 2019-10-15||The line ends on a dedicated support||line_management=termination|
|tower:type=transposing||536 on 2019-10-15||Conductors or bundles configuration or position change||line_management=transpose|
|tower:type=crossing||1369 on 2019-10-15||A support is significantly higher and stronger to allow a line to cross an obstacle like rivers||height=* + design=*|
A whole total of 11 600 objects have to be edited, which doesn't sound so important regarding the 10 millions power towers in OSM and the potential of telecom or misc supports remaining to map worldwide
|Germany||A classical power conductor transposition with help of anchor attachment|
|Germany||Four splits on two separate towers. If you look at connection, you'll see there is no Y connection and it's only independent power systems that change of direction|
|France||A side line connects to the main one (the presence of hanging insulator in the red circle doesn't affect this line management situation)|
|France||The concrete portal should be mapped as a way and the line should connect to it on a power=insulator node. Although a bay line (inside the substation) connects to the incoming line, it's a termination from the management point of view|
|France||A medium voltage power line terminates on a concrete pole to connect to a distribution transformer|
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