Methods, systems, and apparatuses for determining the location or depth in a wellbore of a tubular string or downhole component is provided. One method may include placing a tubular string having a depth measurement module into a wellbore, the wellbore emanating radiation at at least one location along the wellbore and determining the location of the depth measurement module in the wellbore based on a correlation between a wellbore property that is a function of depth and a radiation intensity at at least one location within the wellbore.