Data triangulation refers to the action of using several methods to accumulate data for a particular topic. This is a way to assure the validity of research via the use of different types of samples as well as methods to collect data. The purpose of data triangulation is principally to approach and check the situation or the phenomenon in different lenses or dimensions.
There are different methods in triangulation like Investigator triangulation, theory triangulation, methodological triangulation, environmental triangulation...