A PDF PSA, or Never gonna set_xscale again -- guilty feats with logarithms

Understand

In the course of doing astronomy, one often encounters plots of densities, for example probability densities, flux densities, and mass functions.

• Quite frequently the ordinate of these diagrams is plotted logarithmically to accommodate a large dynamic range.
• In this situation, I argue that it is critical to adjust the density appropriately, rather than simply setting the x-scale to `log' in your favorite plotting code.
• I will demonstrate the basic issue with a pedagogical example, then mention a few common plots where this may arise, and finally some possible exceptions to the rule.