Dear Ethan Thanks for taking this up. I think this approach is sensible.
> 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 ???? ... Yes, I think it's a good idea to say these things. It's in line with the rules (never before used!) about what to do if a mistake is discovered. It would also be appropriate to release 1.8 as soon as we have agreed the change on a trac ticket, with just this ticket included relative to 1.7, so that the corrected version is available for use as soon as possible. Best wishes Jonathan ----- Forwarded message from Ethan Davis <[email protected]> ----- > Date: Wed, 18 Apr 2018 21:39:36 -0600 > From: Ethan Davis <[email protected]> > To: CF metadata <[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 > _______________________________________________ > CF-metadata mailing list > [email protected] > http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ----- End forwarded message ----- _______________________________________________ CF-metadata mailing list [email protected] http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
