Strange tide data

[fabianfisahn]

When I get tide predictions with getExtremesPrediction() I receive strange/ too many data. See my example from Vahemadal (Estonia).
But some are ok, like Helsinki.

Any ideas? I think it changed after you switched to the IHO standard constituents

[bkeepers]

Oh wow, that does not look right. Here's a visualization of it: https://openwaters.io/tides/stations/ticon/vahemadal-vah-est-cmems

I'll do some digging and see what I can find. Do you have another source for local tides that you use there that I can compare to?

[fabianfisahn]

Usually I use Savvy Navvy or Navionics to check tides or to compare with the neaps module.

I just checked Tallinn. Here are online data: https://www.tideschart.com/Estonia/Harjumaa/Tallinn/

See my result from getExtremesPrediction().

[fabianfisahn]

I'm in Olbia/ Sardina at the moment. From my position, all nearby stations looking good.

Is it maybe a Baltic issue because there's almost no tide?

[bkeepers]

Is it maybe a Baltic issue because there's almost no tide?

Very likely. I almost eliminated all the stations with micro tides in openwatersio/tide-database#49, but decided to wait until it was an issue. Now it's an issue 😆

[fabianfisahn]

Is it maybe a Baltic issue because there's almost no tide?

Hmm, but if you compare the real tide data, there is quite a difference. E.g. High Water for Tallinn is 0.56m which is not nothing.

[bkeepers]

See #220 for a pull request to address the extra extremes.

[bkeepers]

Hmm, but if you compare the real tide data, there is quite a difference. E.g. High Water for Tallinn is 0.56m which is not nothing.

My (very limited) understanding is that the Baltic "tides" are affected more by weather (like wind and barometric pressure) than astronomical factors.

[fabianfisahn]

I checked your last changes. It's better but if you check Tallinn again, there are still some extremes very close together (time wise) and don't even have a change (after rounding).
Vahemadal still has way too many. See screenshot for next weekend.