I am working on a project where the hypothesis is along the lines of: the further away the sampling point is from the nearest river, the better the water quality will be. I have plotted the water quality points and coloured them appropriately, but now want to find out if there is a correlation between where the river meets the sea and the water quality.
It is easy enough to calculate distance from the sampling point to the mouth of the river, but how can I see if there is a correlation for each point to its corresponding river?
The rivers and coast are line shapefiles, so for easier analysis I made point shapefiles where the coast and river meet (to indicate where the mouth of the river is).
Thanks for the help