One important topic in fusion research is to identify, how the sources of impurities are distributed between divertor and main chamber, and here, between low and high field side. This distribution of impurity sources determines, together with flows in the Scrape Off Layer (SOL), the spatial distribution of edge impurity radiation and global material transport as well as erosion and deposition patterns. In this paper, we show that Zeeman Spectroscopy yields valuable information on the relative strength of impurity (e.g. carbon) radiation in the inner and outer SOL; the focus here is onto the applicability and reliability of this technique. Conlusions about the corresponding sources, which can be drawn together with other results, will be discussed separately in a future paper.