This is super interesting (Waikawa Beach has a terrible erosion problem in one particular spot) — Cyclone Gabrielle: Parts of East Coast lost 10 metres of shoreline (my emphasis): "Commercially, they've been operating these very high resolution satellites for about the last 20 years, but it's probably only been over the last four or five years that the cost has come down, and the accessibility got to the point where you can order an image on your phone... or you can actually pay a little bit more and task a satellite to be over your beach at a particular time and take an image." He said it cost a... miraz.me

@Miraz Isn’t there an open cartographic data source available in New Zealand? I googled and found this for example. (I don’t know where exactly you’re situated but there seems to be a lot of land covered). In the Netherlands you can compare historic data for a certain location.

@ArnoldHoogerwerf Yup, I’ve used that site before and in fact have a map I made from historic layers using LINZ to show where the erosion is. I asked our local Council to do regular drone surveys to monitor the problem stretch but they can’ afford it. That’s partly why the satellite thing caught my interest. I live about 100 Km north of Wellington.