"NOBODY expects an exegesis in terrestrial frames of reference."
It is kind of handy to be aware that no matter how many decimal places are used to define x,y,z there is still uncertainty. This is especially true when it comes to plotting a well azimuth and inclination. For downhole surveys there are apparently nearly 100 sources of potential error and when horizontal sections can be up to 15000m in length the ellipsoid of uncertainty at the end of the wellbore can be quite large. Even the measurement of length is subject to error. I have never seen the total depth defined by wireline and drillpipe agree in vertical holes and that is over a span of 45 years.

Rather than Monty Python I prefer what have the Romans done for us.

https://www.youtube.com/watch?v=3qTRRBEkesA