Let's say for example, that I have a few weather stations. Each station measures (e.g.) temperature and it's in different location.
Now I'm somewhere between those stations. I know their coordinates and I know my coordinates. How to estimate the temperature in my location?
One of simple methods - build some triangulation for weather stations
find triangle around your location, and use baricentric coordinates
to find weights for infuence of every station. Then estimate temperature as weighted combination:
T(P) = w * T(A) + u * T(B) + v * T(C)