|Shape and function of a physical spot indicating underground utility infrastructure, highway milestones or private property limits|
|Used on these elements|
|Tools for this tag|
A marker often indicates the presence a buried infrastructure nearby, length figures for milestones or limits for private properties. This key allows to describe the shape implied by the function of many markers we see on ground.
It is possible to combinate this key with utility=* in case of infrastructure marker only.
How to map
Once located on ground during a survey or got from public information / street level pictures, just put a node on the exact point and add following tagging on it.
For sake of One_feature,_one_OSM_element, each marker should get its own node on OSM at the exact place it belongs to.
Markers will surely indicate that a particular linear feature (pipeline, power cable...) lies next to it. Nevertheless, markers are installed to be seen and prevent damage at various distances from the feature they refer to. So it's not recommended to put markers directly on pipeline or cable ways, unless the marker is seen fixed on them. Markers are not devices with direct impact or sensing on live features so share nodes between lines and them wouldn't be accurate.
Keep in mind to not add any properties (like diameter=*, pressure=* or voltage=*) that relates to the referring infrastructure on the marker directly. You'd better add them directly on the line of the buried infrastructure. You can still add a note=*, description=* or inscription=* as to not lose information.
Here is a summary of recommended tagging for a utility marker
|marker||<marker shape>||The node corresponds to a marker seen on ground||mandatory|
|utility||<utility>||Activity the marker is referring to if applicable||recommended (if applicable)|
|material||<material>||The material composing most of the marker (referring to the support if dedicated)||optional|
|location||<location>||The physical location of the marker, often overground||optional|
|ref||<marker ref>||If available, the ref as it can be read on the marker||optional|
|operator||<company name>||The name of company who operate the marker (and often the associated linear feature, cable or pipeline)||optional|
|colour||<colour>||The most representative colour of the marker||optional|
|measurement||<value>||If the marker has some kind of measuring box/device attached, this tag describes the kind of measurement provided.||optional|
And a list of possible values for marker=* depending of their design.
This list can be completed as needed with equivalent values valuable in other fields of knowledge if needed.
See examples on values pages instead as it would be redundant.