Hei @erget and all, I happen to have spent the week-end on this projection, browsing through the history, and trying to understand what we were encoding in the CF object. I received great help from the Pytroll community.
I propose a small clarification (against the current 1.9 doc) to: > In the case of this projection, the projection coordinates in this projection > are directly related to the scanning angle of the satellite instrument. First, we have "this projection" twice. Second, "related to the scanning angle". Aren't they the scanning angle themselves, can we drop "related to"? Third, it seems to me that this projection introduces a mismatch between what is stored in the CF file (the angles in radians) and what "mainstream" projection libraries (Proj) use (distance from origin in meters). So that the wording "the projection coordinates" could be confusing. Thus, I humbly suggest: > In the case of this projection, the x and y coordinates stored in the file > are directly the scanning angles of the satellite instrument. I also suggest a sentence to be added in the bullet points, to warn the non-expert user, along the lines of: > Note that the CF convention stores the scanning angles (with canonical unit > gradients) as the coordinates for this projection, while the popular library > PROJ uses distance from origin (meters). I understand the implementation in PROJ shouldn't be driving the CF convention (and it didn't), but I feel we could be explicit for the non-expert users (after all, AFAIK, the geostationary projection is the only one in CF where CF stores something different that what PROJ returns/expects). -- You are receiving this because you are subscribed to this thread. Reply to this email directly or view it on GitHub: https://github.com/cf-convention/cf-conventions/pull/259#issuecomment-626590532 This list forwards relevant notifications from Github. It is distinct from [email protected], although if you do nothing, a subscription to the UCAR list will result in a subscription to this list. To unsubscribe from this list only, send a message to [email protected].
