I have climate data (average annual rainfall) from weather stations in a region. I have created three different point layers of the climate data according to data quality: (1) only stations in which 100% of the data is from field measurement (eliminates stations with patched information); (2) stations in which field measurement is equal or higher than 90% of the year; and (3) all stations. The higher the data quality, the smaller the number of stations available: (1) 126 stations, (2) 375 stations, and (3) 737 stations.
I would like a method to define a suitable spatial resolution for the grid generated with those point layers that fit the number and location of the stations (spatial resolution optimised for the data set characteristics). I want to avoid an arbitrary decision on 1 Km, 5 Km, 10Km, and 50 Km for my interpolated surface.