Wow advanced combat coordinates explained

Hello! I am hoping someone might spend some time to explain wow’s advanced combat coordinates system. I am trying to figure out how to place a marker on a grid similar to warcraft log’s replay functionality. For example, what does wow consider the coordinate origin? Top left? Bottom right? Does every zone have it’s own coordinate grid? Are they related in some way or are they completely independent? Please forgive me if these questions are too broad, I’ve been looking for resources that cover this online, but I’ve come up blank. If there’s a good source overview, I’d appreciate a pointer. Thanks!

So, some things I’ve been able to piece together (please feel free to correct any of this if anyone knows better)…

  1. wow map coord origin (0, 0) seems to be bottom right corner (so opposite of html canvas for example).
  2. is a pretty good tool to help figure out coordinate dimensions of various wow zones
  3. in the advanced combat logging parameters, the y coordinate comes first (so y, x) for some reason

This has been enough info for me to be able to take the coordinates from the advanced combat log and make sense of them for replay purposes. If anyone has any further tips or tricks, please jump in.