I have a dataset of species distribution in latitudes and longitudes extracted from geo-tagged photographs. I have plotted them on a map to see how distribution looks like. My attempt was to check whether this distribution falls within the previously documented species distribution range. For this, I have the data (lat. and long.) of the previously documented species range. I have overlayed these documented data over the map which I have created. To be more precise, I have read that I can buffer the documented points. My problem is how to determine the buffer distance for each point for documented latitude and longitude. I have read that I can use uncertainty range for this (e.g. let's say 20km from a point).
How do I calculate this uncertainty from the decimal coordinates that I have?
I'm new to GIS.