Add a transform class from desimeter to platemaker focal plane coordinates (desimeter.transform.dm2pm). The transform is one again based on Zhao Burge polynomials.
Add data file with best fit transform based on a stack of the PM and DM fiberassign coordinates from 20210512
Use this in the fiberassign transformation functions by default.
Example (based on an exposure not used for the fit):
Coverage increased (+0.2%) to 73.349% when pulling 99458ef41ab07afb957e772405ab5dcab459d6f9 on dm2pm into ea5236a484518b156a8d9a0b7f2fc63ef62c0d35 on master.
Example (based on an exposure not used for the fit):
RMS residuals of 8 microns. Max deviation: 20 microns, for an exposure at an elevation of 57deg.