Ethan, Thanks for your quick action on this. Analysis of the GOES-R product definitions is beginning for the change to the two newly proposed standard names. As written, the new standard name definitions are fine with us.
Michael Carlomusto GOES-R Ground System Harris Corporation, Melbourne, FL [email protected]<mailto:[email protected]> NOAA Satellite Operations Facility, Suitland, MD [email protected]<mailto:[email protected]> From: CF-metadata [mailto:[email protected]] On Behalf Of Daniel Lee Sent: Thursday, April 19, 2018 5:06 AM To: Ethan Davis <[email protected]>; CF metadata <[email protected]> Subject: Re: [CF-metadata] Fix Geostationary projection, including proposal for two new standard names Hi Ethan, At first blush this looks pretty good. If we can agree on this in a short-ish time frame, it might be possible for EUMETSAT to publish data exclusively using these standard names - the planned launch date for MTG I1 is late 2021. This sounds like it's very far away, but in the space sector our planning horizons are a lot longer, so there's already a lot of work being done on it right now and at some point in the near future the specs will freeze. Best regards, Daniel From: CF-metadata [mailto:[email protected]] On Behalf Of Ethan Davis Sent: 19 April 2018 05:40 To: CF metadata <[email protected]<mailto:[email protected]>> Subject: [CF-metadata] Fix Geostationary projection, including proposal for two new standard names Hi all, Here's an initial proposal for fixing the geostationary projection as we've been discussing. Two new standard names: Name: projection_x_angular_coordinate Canonical units: radian Definition: "x" indicates a vector component along the grid x-axis, when this is not true longitude, positive with increasing x. Angular projection coordinates are angular distances in the x- and y-directions on a plane onto which the surface of the Earth has been projected according to a map projection. The relationship between the angular projection coordinates and latitude and longitude is described by the grid_mapping. Name: projection_y_angular_coordinate Canonical units: radian Definition: "y" indicates a vector component along the grid y-axis, when this is not true latitude, positive with increasing y. Angular projection coordinates are angular distances in the x- and y-directions on a plane onto which the surface of the Earth has been projected according to a map projection. The relationship between the angular projection coordinates and latitude and longitude is described by the grid_mapping. Replace the text of the current "Map coordinates:" section with The x (abscissa) and y (ordinate) projection coordinates are identified by the `standard_name` attribute values `projection_x_angular_coordinate` and `projection_y_angular_coordinate` respectively. In the case of this projection, the projection coordinates are directly related to the scanning angle of the satellite instrument. Add a deprecation note below the current "Notes:" Deprecation Note: The use of `projection_x_coordinate` and `projection_y_coordinate` for this projection has been deprecated. The initial definition of this projection used these standard names to identify the projection coordinates even though their canonical units (meters) do not mach those required for this projection (radians). Perhaps we should include information on when the deprecated feature was in effect: The initial definition for this projection was agreed on in May 2012 though it was not in the CF document until 1.7 was released in Sept 2017. It was corrected in ??? 2018. And do we also want to include information about large datasets that use this deprecated technique: In that time, several satellite missions were developed and launched that generate data that use this now deprecated method including GOES-R (operational in Dec 2017), EUMETSAT ???? ... That could alert people to the likelihood they (or any software they develop) might run into data using this deprecated feature. I'll move this to a Trac ticket (with an accompanying GitHub PR) once we discuss a bit. Cheers, Ethan Any email message from EUMETSAT is sent in good faith but shall neither be binding nor construed as constituting a commitment by EUMETSAT, except where provided for in a written agreement or contract or if explicitly stated in the email. Please note that any views or opinions presented in this email are solely those of the sender and do not necessarily represent those of EUMETSAT. This message and any attachments are intended for the sole use of the addressee(s) and may contain confidential and privileged information. Any unauthorised use, disclosure, dissemination or distribution (in whole or in part) of its contents is not permitted. If you received this message in error, please notify the sender and delete it from your system.
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