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The widely used coordinate system (B,L) has proved very suitable for most of the region covered by the Van Allen belts, but is not very well suited for the low‐altitude regions where the Earth’s atmosphere interacts with the trapped particle population. Several alternative coordinate systems have been proposed that aim to take into account the steep flux gradients in the region of the upper atmosphere. An overview of these coordinates is presented. The effectiveness of each system is assessed by mapping the proton flux distribution of NASA’s AP‐8 model. Special attention is given to Hassitt’s weighted average of the atmospheric density over the drift shells of trapped particles, which appears very efficient in mapping fluxes for low L values.