Key:line attachment

Line attachment is about how wires, cables or conductors are bound to their supports. Depending of distances, environment and climate conditions, engineers have to choose between suspension or anchorage.
Additional situations can be found on lines extremities or branches.
Definitions are linked on each value of this key.

This information is useful for power and telecom wires, the last doesn't involve insulators. Then it's more appropriate to deal with standard attachment and share those concepts instead of documenting proper insulators. Additional keys could be defined to complete the tagging and give more details about insulators sets/chains.
line_attachment=* and line_management=* are also intended to free tower:type=* and pole:type=* from defining how lines connect to supports.

Here is the list of considered values for this key:

How to map

From ground, go near of the line support you want to document and look at how conductors or cables are bound to it according to definitions upside.
Choose the value or combine the values accordingly.

From aerial imagery, shadows and direct views of corresponding support may be good help to find the same information.
Picture beside shows a very suitable situation where the shadow is clearly readable.
line_attachment=suspension should be used for that power tower.

Complex configurations

As some supports may have a complex arrangement of line attachments, a matrix tagging may allow us to give all details about this.
We could use pipes and parenthesies as follow to describe such cases, according to picture beside: line_attachment=(suspension|pin|suspension)|(anchor)|(suspension)

The pipe | separates sections and levels, i.e the arrengement of attached lines on the support at a given level and different level as well.
Then the first level is accordingly suspension|pin|suspension.
The second level is simpler anchor
The third level is also simple suspension
This is equivalent to what was chosen to tag highways/railway lanes and described in according article.

Values would be given from left to right / top to down of the pole in the direction of the drawn way passing by the supporting node.
Chart below summarise many possibilities:

See also

• Diary: Improving power tower/poles mapping without tower:type