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 academic buyers about $20 per square kilometre. The higher the resolution, the higher the cost, but it was a gamechanger for scientific research, he said.