I'm working off the acceptable licence LPI NSW topo and base map. These contain both spot heights

  • node 4095589851
  • ele=126.8
  • natural=spot_elevation
  • source=NSW LPI Topographic

and true peaks

  • node 3019437976
  • ele=156
  • name=Stony Rise
  • natural=peak

is this correct tagging form?

I feel comfortable that spot_elevations should be tagged in the area I'm tagging. The land is very flat, making surveyed peaks and spot_elevations significant. They're usually the only feature within 1-10 km. The feature density is one to two spot_elevations per 0.10º x 0.10º, the general feature density is low. The data source for peaks & spot_elevations is the government's Land and Property Information so the data quality is good.

The question isn't should I tag them, they're useful verifiable data for an uninhabited area with significant navigation issues and hazards to life. The question is how ought they be tagged.

asked 06 Apr '16, 04:12

samuelrussell's gravatar image

samuelrussell
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accept rate: 0%

edited 06 Apr '16, 07:27

1

Are you surveying the area, or are you simply copying (or even importing) data from the government data set?

(06 Apr '16, 08:35) Frederik Ramm ♦

I am simply copying from rendered tiles from our contributor https://wiki.openstreetmap.org/wiki/Contributors#New_South_Wales_Government_data (CC-BY 3.0) cross-referencing two sets of rendered tiles against their imagery and satellite / air imagery. I assume that the LPI's original surveyors had good mapping reason to include the one to two survey heights per square 0.10º. There's occasional satellite / air-mapping of out-buildings, sheds, hedges, but that doesn't go to the spot_elevation issue.

(06 Apr '16, 10:09) samuelrussell

We don't normally map spot elevations at all (just as we don't map sea depths). Where would you stop? How many spot elevations per square metre would be acceptable?

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answered 06 Apr '16, 06:33

Frederik%20Ramm's gravatar image

Frederik Ramm ♦
69.9k806321096
accept rate: 24%

3

This question comes up often in OSM circles. As Frederick states, under normal circumstances we don't officially map spot heights, but as usual there are exceptions. If that spot is the highest point in an otherwise flat environment it might warrant a node and an elevation tag. However, tagging such a node as a "peak" doesn't seem quite right even then. Yet that is the only possibility available under the currently acceptable OSM tagging scheme. Even the "true peak" you mention in your post is barely a bump compared to most features I would consider peaks.

(06 Apr '16, 07:15) AlaskaDave

The back of beyond in Australia is far from a normal scenario.

(06 Apr '16, 07:18) samuelrussell

In areas where you should map spot_elevations, you should probably just tag them as natural=spot_elevation. I agree that the number of the areas where you should map spot_elevations is exceeding small.

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answered 10 Apr '16, 07:30

samuelrussell's gravatar image

samuelrussell
1163310
accept rate: 0%

1

"natural=spot_elevation" is currently only used 7 times worldwide:

http://taginfo.openstreetmap.org/tags/natural=spot_elevation

Spot heights elsewhere have tended to just use an ele tag:

http://taginfo.openstreetmap.org/keys/ele#overview

Is there anything "separately worth mapping" about a spot height other than its height?

That said, there's definitely a problem in some places (e.g. the UK) with people copying spot heights from out of copyright maps and tagging them as "natural=peak" so that they render on the "standard" map (without survey, so of course some "peaks" are now at the bottom of quarries!). Maybe a tag like this might be a solution to that.

(10 Apr '16, 10:14) SomeoneElse ♦
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question asked: 06 Apr '16, 04:12

question was seen: 1,639 times

last updated: 10 Apr '16, 10:14

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