Proposal:Survey Markers

Survey Markers
Proposal status:	Approved (active)
Proposed by:	Kylenz
Tagging:	survey_point:structure=beacon/block/pillar/pole/bracket/plaque/medallion/pin/indented_pin/cut/magnet, survey_point:datum_aligned=yes/no, survey_point:purpose=horizontal/vertical/both=*
Applies to:
Definition:	The structure, condition, and purpose of a survey marker.
Draft started:	2021-06-03
RFC start:	2021-06-04
Vote start:	2021-06-20
Vote end:	2021-07-04

Proposal

This proposal seeks to create a standard way of defining the structure, condition, and purpose of survey markers, which are tagged as man_made=survey_point.

It also seeks to formally approve the use of man_made=survey_point, which is used 354,000 times and has a status of de-facto.

Following feedback, this proposal will not deprecate the undocumented & messy tag survey_point=*.

Rationale

The tag man_made=survey_point is widely used, however there is no standard way of defining the type and condition of the survey marker.

Current tagging methods:

• survey_point=* is used on 12,000 nodes without any formal description of how to use that tag. The type of values used vary considerably (see taginfo).
• During the 2012 New Zealand import, various non standard tags were coined to describe survey points (LINZ:mark_condition=*, LINZ:mark_type=*, LINZ:beacon_type=*, LINZ:coordinate_order=*). Used on 6,300 nodes.
• Using description=* to describe the survey marker (166,000 nodes)
• Using note=* to describe the survey marker (180,000 nodes)

Tagging

Create a node, tagged with man_made=survey_point.

It can be combined with the following existing tags: name=*, ele=*, ref=*, operator=*, description=*.

It can also be combined with the following three new tags: survey_point:structure=*, survey_point:datum_aligned=*, survey_point:purpose=*. See the tables below.

Structure

Tag	Description	Example
survey_point:structure=beacon	A large structure, typically four-legged, visible from a far distance. Sometimes called a Trig Station. Common in Australia and New Zealand. Can be combined with height=* to describe the height of the trig station (usually 2 to 4 metres).	File:Trig-Station.jpg
survey_point:structure=block	A solid block that sits on the ground, generally on a small concrete foundation.
survey_point:structure=pillar	A pillar - generally smaller and more slender than a block.
survey_point:structure=pole	A pole is much more slender and generally taller than a pillar. In the photo, there are two poles. The shorter pole in the foreground is also a valid example of a pole
survey_point:structure=bracket	A plaque-like bracket that allows equipment to be hooked into it. If you cannot hook equipment into it, then it is a plaque (see below)	A projecting bracket
survey_point:structure=plaque	If there is only a plaque, and no other structure. Use bracket (see above) if the plaque allows you to connect survey equipment.
survey_point:structure=medallion	Circular plate embedded at the surface of a larger structure, typically a building. Survey instruments may be inserted in it for measures.
survey_point:structure=pin	If there is no physical structure, besides from the pin/bolt itself. See also: indented_pin In the photo, the pin has a circle spray-painted around it. This does not count as a structure.
survey_point:structure=indented_pin	Similar to pin, except that it has an indent for inserting survey equipment
survey_point:structure=cut	A line cut into a wall or rock
survey_point:structure=magnet	If the survey marker is an underground magnet. Please combine with location=underground	Example

Condition

Tag	Description
survey_point:datum_aligned=yes	If the location of the marker is known to be reliably aligned to the nearest Geodetic datum.
survey_point:datum_aligned=no	If the location of the marker is NOT aligned to the local Geodetic datum. This may be because of an earthquake/landslide/flood, or it was moved accidently or moved by growing tree roots.

Purpose

Tag	Description
survey_point:purpose=horizontal	Often called a Triangulation Point, this is used in geodetic surveys to measure horizontal distance between objects.
survey_point:purpose=vertical	Often called a Benchmark. Used to measure difference in elevation.
survey_point:purpose=both	If a marker can be used for both horizontal and vertical triangulation

Notes

• If a survey marker has been destroyed, you may replace man_made=survey_point with destroyed:man_made=survey_point if you really want to map it, but keep in mind Good practice.
• If a survey marker still exists but is no longer visible, you could add location=underground. For marks embedded into the roadway, resealing the road may have covered the pin. Another example is if a building was constructed on top of the marker

Examples

see photos above. Example OSM node for beacon: 2229792701 2229792701

Rendering

This proposal does not suggest rendering man_made=survey_point because currently, the tagging scheme does not distinguish between the structure of the survey marker.

However, if this proposal is successful, it may be useful to render survey_point:structure=beacon since they are significant landmarks. This is outside the scope of this proposal.

suggested by User:Chrisana13

Features/Pages affected

• Tag:man_made=survey_point

External discussions

• Discussion on the 'tagging' mailing list

Comments

Please comment on the discussion page.

Voting

Voting closed

Voting on this proposal has been closed.

It was approved with 13 votes for, 2 votes against and 5 abstentions.

• I approve this proposal. --Kylenz (talk) 23:40, 20 June 2021 (UTC)
• I approve this proposal. --Tokada (talk) 02:52, 21 June 2021 (UTC)
• I approve this proposal. --Carnildo (talk) 02:55, 21 June 2021 (UTC)
• I approve this proposal. --Javiersanp (talk) 06:31, 21 June 2021 (UTC)
• I approve this proposal. --Hauke-stieler (talk) 08:13, 21 June 2021 (UTC)
• I approve this proposal. --Gruebel (talk) 08:40, 21 June 2021 (UTC)
• I have comments but abstain from voting on this proposal. A way too short period of time to evaluate impact of survey_point:purpose=* (introduced on june 20). I still wish to complete existing marker=* instead of introducing specialized survey_point:structure=* Fanfouer (talk) 10:19, 21 June 2021 (UTC)

Discussion goes on Talk page.

• I have comments but abstain from voting on this proposal. How survey_point:purpose=horizontal survey_point:purpose=vertical survey_point:purpose=both can be distinguished and verified by mappers? Mateusz Konieczny (talk) 10:50, 21 June 2021 (UTC)

In the United States, USGS markers have different symbols on them depending on the type, while PLSS markers are always horizontal-control. I suspect there are similar situations in other countries. --Carnildo (talk) 18:05, 21 June 2021 (UTC)

• I oppose this proposal. As said above, using the tag marker=* seems much better, and could be extended for this kind of items. And could we imagine to use utility=survey_point for this marker ? --Zorglubu (talk) 11:11, 21 June 2021 (UTC)

Hi @Zorglubu:, there was a lengthy discussion about this on both the wiki talk page, and on the tagging mailing list. There are 3 significant issues with using marker=* that can't be overcome (summarized here). So unfortunately it is not practical to use marker=* - did you vote no because you think we can overcome these issues? I would love to here your suggestions --Kylenz (talk) 22:40, 21 June 2021 (UTC)

How is surveying a "utility"? Unless you count ground-based GNSS CORS network. ---- Kovposch (talk) 07:33, 22 June 2021 (UTC)

• I approve this proposal. --Elgaard (talk) 11:53, 21 June 2021 (UTC)
• I oppose this proposal. marker=* should be used and is established for the very same purpose and survey points which are not part of a geodetic network. No need for a "namespaced" new key describing the very same characteristics. A very major and important concept 'underground marker" is not described. The "nearest geodatic datum" is not deterministic. The exact datum name should be used as geodetic datums might be different. The proposal should include verifiable data which allows a mapper to "conclude" if a marker is moved or not, accuracy etc... The survey_point:purpose=* and scope of this proposal should also describe use of this tag for survey points not part of a geodetic system. The discussion period for this proposal was too short. --Bert Araali (talk) 12:57, 21 June 2021 (UTC)

Hi, @Bert Araali:, there are 3 unavoidable issues that prevent us from using marker=*, there was a long discussion about this on the wiki talk page, and on the tagging mailing list. Also you are welcome to include the exact datum name under survey_point:system=*, which is already in use (so not part of the proposal). Regarding underground markers, following feedback I have changed the proposal to only suggest adding location=underground if it is underground (such as an underground magnet, tagged with survey_point:structure=magnet) This is my first tag proposal, I followed the instructions in the week about having a two-week period for comments, all of which were resolved - is the wiki page wrong about 2 weeks? --Kylenz (talk) 22:40, 21 June 2021 (UTC)

3 unavoidable issues was open for only two days. The unavoidable issues might not be so unavoidable, well described by François Lacombe on the mailing list. Underground markers are not necessarily completely underground, it means they are vertically stacked so the above ground or visible part can be properly repositioned in case of misplacement after surface activities or vandalism. They are referenced with this term in many geodetic systems. location=underground doesn't address this "structure" accurately. Although I followed the whole discussion in detail, I did not participate since most of the issues were addressed by other mappers. Your effort to start making your "first" proposal is much appreciated. 2 weeks for RFC is a "minimum" guideline, let the discussion go as long as it needs to get common ground. The number of abstain votes proves it's not biased enough to make it conclusive. You touched a very sensitive and complicated subject "surveying and map calibration", brave and bold but in my opinion asks for a much more comprehensive approach and proposal then just trying to describe the "structure" of a survey point with unfavourable namespaced keys, ambiguous with an existing attribute.

• I have comments but abstain from voting on this proposal. I have doubts about the difference between survey_point:structure=bracket, survey_point:structure=indented_pin and survey_point:structure=medallion, as I just realized they seem to represent essentially the same thing: a survey point which allows to insert equipment; only the shape varies, but the use of the survey point is essentially the same. --Penegal (talk) 15:37, 21 June 2021 (UTC)

Hi @Penegal:, you're right, they are similar but their structure is rather different. There is no harm in having more values, right? So it is very helpful to know exactly what structure you are looking for --Kylenz (talk) 22:40, 21 June 2021 (UTC)

• I approve this proposal. --Nw520 (talk) 22:52, 21 June 2021 (UTC)
• I have comments but abstain from voting on this proposal. Since we already have a top-level tag of "marker," it seems counter-intuitive to not make survey markers a subset of the top-level tag, despite the problems you mention. Also, whether this proposal passes with the top-level tag being man_made or marker, I think you should add another value to the structure type choices: a metal disk. (Example at https://www.lamag.com/citythinkblog/mystery-marker/.) These are very common in the United States. --Dr Centerline (talk) 00:18, 22 June 2021 (UTC)
• I approve this proposal. --Timmy_Tesseract (talk) 04:37, 22 June 2021 (UTC)
• I have comments but abstain from voting on this proposal. I'm somewhat ok with the hastily introduced survey_point:purpose=*, but it may be confused as the outcome of survey (eg land acquisition, construction, datum). Directly as survey_point:control=* or similar is better. ---- Kovposch (talk) 07:49, 22 June 2021 (UTC)
• I approve this proposal. --Thomas Jarvis (talk) 16:48, 22 June 2021 (UTC)
• I approve this proposal. --EneaSuper (talk) 11:02, 27 June 2021 (UTC)
• I approve this proposal. --Reino Baptista (talk) 15:30, 27 June 2021 (UTC)
• I approve this proposal. --TheBlackMan (talk) 16:19, 28 June 2021 (UTC)