I have only just spotted your article, which was very helpful and gave me a good starting point and i just wanted to say thanks.
Having got this up and running I decided to add a breakdown of the water height at minute intervals, which is helpful if you live on an estuary.
Then of course I realised that this method is not strictly accurate as you are not calculating the current postion of the tide, but the next cycle, which can have a lower or higher, high/low tide. If you are calculating tides around the Isle of Wight/Poole UK area, this will probably be less accurate as they have 2 high tides per day.
Your method is very simple and it’s not far out, but I decided to re-work this in Node-Red as it became a little complicated. If anyone wants my Node-Red flow, give me a shout.
