  Generally, identifying the spiral arms of a spiral galaxy is not a hard task.
However, defining the main characteristics, width and length of those structure
is not a common task. Previous studies have used different tracers: Star
clusters, Massers, H$\alpha$. It was until recently that individual stars were
used as tracers of spiral structures. The basic method of measuring the width
of spiral arms assumes a Gaussian distribution around the mean concentration,
either of gas or other tracer. In this work we use NGC 5236's stars as tracers.
We estimated the surface stellar density of arms and inter-arm regions to
measure the width of the arms. As a test case, this works focused on NGC 5236
(M83). We find that field stellar populations can trace the (two) main spiral
arms of NGC 5236. We find a correlation between the arm width and the
galactocentric radii, found using other tracers. The slope of the growth of the
width of the arm correlates with the morphological types of spiral galaxies. A
second finding of our study suggest the possible correlation between the width
of the arms and the corrotation radius, result that will be presented in a
follow up paper.
