In practice I don't know of any geostationary data that has a non-zero `latitude_of_projection_origin`. However, this is normally a by-product of rectification. Most geostationary products are produced by satellites that are, in fact, geosynchronous - the satellite doesn't stay consistently above a single point on the Earth, as this would expend a lot of fuel, but rather "wobbles" in a figure-eight about its nominal point. This wobble can actually take the satellite several degrees above and below the 0° latitude line.
Users never notice this because before products go out they are rectified, so it looks like the satellite was always over the same point, but if someone were to use a geostationary projection to provide geolocated but unrectified imagery, some of the products in a timeline might have a non-zero latitude at origin. I'm not sure what NOAA's doing but my feeling says that PROJ's interpretation is right, so it might be worthwhile to be explicit about this in the Conventions. -- 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/issues/246#issuecomment-586203309 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].
