Proposal talk:Tag:natural=mean high water neaps

Is this tag necessary?

I appreciate your related proposal for natural=mean_low_water_springs as a way to map the low tide line, to complement the natural=coastline at the high tide line ("mean high water springs" in theory). It's twice as much work to map both the high and low tide lines, but many mappers have already started doing this by mapping the area of beaches, tidal flats, mangroves and salt marshes which are found between the low and high tide lines, so it's a good idea to formally propose a tag. But on the other hand, I haven't seen or heard of anyone wanting to map the average neap tide lines. Adding these would again double the amount of mapping work required.

Are you planning to do this yourself, in your area? How would you determine the mean high water neaps and mean low water neaps line in your area? Except for importing the information from an official source, I have trouble imagining how this could be done practically, and in the USA this information isn't recorded by the government (though they do measure the mean high water springs and mean low water springs, and show these on some public domain topo maps).

Ideally all tags should be for something that individual local mappers can confirm to be correct or wrong by visiting the feature, but to measure the mean high water neaps you would need to visit at 2 times many hours apart, and then again 14 days later another 2 times, for each stretch of coast, or find aerial imagery at that precise time which is rather unlikely. --Jeisenbe (talk) 03:37, 6 September 2019 (UTC)

Yes, I know it's a little fuzzy, but it's kind of verifiable, specialy in certain areas where this tag is most useful, like places with huge intertidal zones, mainly beaches. You can walk with your GPS every fifteen days along this line and correct the way if needed. Obviously the neap tides are second tier map content compared with the spring tides, but none the less it may prove useful in the future, as many things we considered imposible a few years ago are important features of OSM now. I'd leave it as a proposed feature just in case. --Iagocasabiell (talk) 00:58, 7 September 2019 (UTC)

No, you can't. You need to do that at low tide (+/-10 min?) when the preasure is of 1013 hPa, without waves. In my area the beaches have more sand in summer than in winter (by about 50 cm - in height), moving the line around the year, not speaking about storms and current moving the sand. Could be interesting to inform about the shape of the beaches but then the high tides are more interesting. For that we have the DEMs as it's above mean sea level. More interesting is the HAT (highest astronomical tide) as it's used for instance in France and Germany to limit the communes: after the HAT (seaward) it's the maritime public domain. Anoter interesting line is the LAT (used by most nautical charts). MSL, LAT, HAT are easier to find than MHWN and MLWN. --Nospam2005 (talk) 20:53, 22 May 2020 (UTC)