Re: [CF-metadata] CF-convention for three-dimensional lat/long coordinate variables?
Hi, John! On Wed, Mar 10, 2010 at 9:27 AM, john caron wrote: > It appears that d0 is a time dimension? If so, CF would require a time > coordinate for it. I don't know its precise physical meaning but the real interesting part is that lat/lon positions are recorded in 3-D array since most EOS swath has 2-D array lat/lon coordinate variables. The data has a separate time variable in 3-D array as well. In CF-1.4 two dimensional coordinate system, I believe that the name and the number of dimensions are not significant as long as they are unique enough to associate between coordinate variables and variables. > In any case, its necessary to distinguish between "CF > compliant" and "able to be georeferenced by generic programs using CF > metadata". The latter is more stringent, and at the moment i dont think your > dataset has enough info. I agree that the latter is more stringent. I often feel frustrated by the gap between "CF-compliant"-ness of data and "geo-referencing capability of the real softwares using CF metadata". However, I think my data has enough information to be plotted on the World map if softwares are smart enough to pick up lat/lon coordinate variables represented in 3-D, 4-D, ... n-D. > > > H. Joe Lee wrote: >> >> Thanks, Karl! Maybe, I think it's good to mention this possibility >> in the CF document: coordinate variables can be arbitrary n-Dimension >> arrays where n > 1. >> >> Regarding the 3rd dimension, the 3-D lat/lon coordinate variables >> have dimension names like below. >> >> 447 (Number of HourBoxes) x 3 (1.0 deg. Colat Zones: 178 - 180) x >> 360 (1.0 deg. longitude regions) >> >> >> -- >> +1(217)265-7710 >> http://hdfeos.org >> >> >> >> On Fri, Mar 5, 2010 at 4:14 PM, Karl Taylor wrote: >> >>> >>> Hi, >>> >>> This file looks CF-compliant to me. I don't think it has to be 2-d. >>> Like >>> John Caron, I am mildly curious what the 3-dimensions represent. >>> >>> regards, >>> Karl >>> >>> On 05-Mar-10 12:30 PM, H. Joe Lee wrote: >>> Hi, I have a satellite data that stores lat / lon information in 3-D array and I'm wondering how such data can meet the CF convention. Following the http://*cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s02.html page example convention, here's the description of my data: - dimensions: d0 = 447 ; d1 = 3 ; d2 = 360; lev = 18 ; variables: float V(lev,d0,d1,d2) ; T:long_name = "Precipitable Water" ; T:units = "cm" ; T:coordinates = "lon lat" ; float lev(lev) ; lev:long_name = "pressure level" ; lev:units = "hPa" ; float lon(d0,d1,d2) ; lon:long_name = "longitude" ; lon:units = "degrees_east" ; float lat(d0,d1,d2) ; lat:long_name = "latitude" ; lat:units = "degrees_north" ; --- My question is, should lat / lon coordinate variables be always 2-D array in CF-convention for two dimensional coordinate system? Thanks, -- +1(217)265-7710 http://*hdfeos.org ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://*mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >>> >>> >> >> ___ >> CF-metadata mailing list >> CF-metadata@cgd.ucar.edu >> http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> > > ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] CF-convention for three-dimensional lat/long coordinate variables?
It appears that d0 is a time dimension? If so, CF would require a time coordinate for it. In any case, its necessary to distinguish between "CF compliant" and "able to be georeferenced by generic programs using CF metadata". The latter is more stringent, and at the moment i dont think your dataset has enough info. H. Joe Lee wrote: Thanks, Karl! Maybe, I think it's good to mention this possibility in the CF document: coordinate variables can be arbitrary n-Dimension arrays where n > 1. Regarding the 3rd dimension, the 3-D lat/lon coordinate variables have dimension names like below. 447 (Number of HourBoxes) x 3 (1.0 deg. Colat Zones: 178 - 180) x 360 (1.0 deg. longitude regions) -- +1(217)265-7710 http://hdfeos.org On Fri, Mar 5, 2010 at 4:14 PM, Karl Taylor wrote: Hi, This file looks CF-compliant to me. I don't think it has to be 2-d. Like John Caron, I am mildly curious what the 3-dimensions represent. regards, Karl On 05-Mar-10 12:30 PM, H. Joe Lee wrote: Hi, I have a satellite data that stores lat / lon information in 3-D array and I'm wondering how such data can meet the CF convention. Following the http://*cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s02.html page example convention, here's the description of my data: - dimensions: d0 = 447 ; d1 = 3 ; d2 = 360; lev = 18 ; variables: float V(lev,d0,d1,d2) ; T:long_name = "Precipitable Water" ; T:units = "cm" ; T:coordinates = "lon lat" ; float lev(lev) ; lev:long_name = "pressure level" ; lev:units = "hPa" ; float lon(d0,d1,d2) ; lon:long_name = "longitude" ; lon:units = "degrees_east" ; float lat(d0,d1,d2) ; lat:long_name = "latitude" ; lat:units = "degrees_north" ; --- My question is, should lat / lon coordinate variables be always 2-D array in CF-convention for two dimensional coordinate system? Thanks, -- +1(217)265-7710 http://*hdfeos.org ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://*mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] CF-convention for three-dimensional lat/long coordinate variables?
Thanks, Karl! Maybe, I think it's good to mention this possibility in the CF document: coordinate variables can be arbitrary n-Dimension arrays where n > 1. Regarding the 3rd dimension, the 3-D lat/lon coordinate variables have dimension names like below. 447 (Number of HourBoxes) x 3 (1.0 deg. Colat Zones: 178 - 180) x 360 (1.0 deg. longitude regions) -- +1(217)265-7710 http://hdfeos.org On Fri, Mar 5, 2010 at 4:14 PM, Karl Taylor wrote: > Hi, > > This file looks CF-compliant to me. I don't think it has to be 2-d. Like > John Caron, I am mildly curious what the 3-dimensions represent. > > regards, > Karl > > On 05-Mar-10 12:30 PM, H. Joe Lee wrote: >> >> Hi, >> >> I have a satellite data that stores lat / lon information in 3-D >> array and I'm wondering how such data can meet the CF convention. >> >> Following the >> http://*cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s02.html >> page example convention, here's the description of my data: >> >> - >> dimensions: >> >> d0 = 447 ; >> d1 = 3 ; >> d2 = 360; >> lev = 18 ; >> >> variables: >> float V(lev,d0,d1,d2) ; >> T:long_name = "Precipitable Water" ; >> T:units = "cm" ; >> T:coordinates = "lon lat" ; >> float lev(lev) ; >> lev:long_name = "pressure level" ; >> lev:units = "hPa" ; >> float lon(d0,d1,d2) ; >> lon:long_name = "longitude" ; >> lon:units = "degrees_east" ; >> float lat(d0,d1,d2) ; >> lat:long_name = "latitude" ; >> lat:units = "degrees_north" ; >> --- >> >> My question is, should lat / lon coordinate variables be always 2-D >> array in CF-convention for two dimensional coordinate system? >> >> Thanks, >> >> -- >> +1(217)265-7710 >> http://*hdfeos.org >> ___ >> CF-metadata mailing list >> CF-metadata@cgd.ucar.edu >> http://*mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata >> >> >> > > ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] CF-convention for three-dimensional lat/long coordinate variables?
Hi, This file looks CF-compliant to me. I don't think it has to be 2-d. Like John Caron, I am mildly curious what the 3-dimensions represent. regards, Karl On 05-Mar-10 12:30 PM, H. Joe Lee wrote: Hi, I have a satellite data that stores lat / lon information in 3-D array and I'm wondering how such data can meet the CF convention. Following the http://*cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s02.html page example convention, here's the description of my data: - dimensions: d0 = 447 ; d1 = 3 ; d2 = 360; lev = 18 ; variables: float V(lev,d0,d1,d2) ; T:long_name = "Precipitable Water" ; T:units = "cm" ; T:coordinates = "lon lat" ; float lev(lev) ; lev:long_name = "pressure level" ; lev:units = "hPa" ; float lon(d0,d1,d2) ; lon:long_name = "longitude" ; lon:units = "degrees_east" ; float lat(d0,d1,d2) ; lat:long_name = "latitude" ; lat:units = "degrees_north" ; --- My question is, should lat / lon coordinate variables be always 2-D array in CF-convention for two dimensional coordinate system? Thanks, -- +1(217)265-7710 http://*hdfeos.org ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://*mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
Re: [CF-metadata] CF-convention for three-dimensional lat/long coordinate variables?
what does the 3rd dimension represent ? On 3/5/2010 1:30 PM, H. Joe Lee wrote: Hi, I have a satellite data that stores lat / lon information in 3-D array and I'm wondering how such data can meet the CF convention. Following the http://cf-pcmdi.llnl.gov/documents/cf-conventions/1.4/ch05s02.html page example convention, here's the description of my data: - dimensions: d0 = 447 ; d1 = 3 ; d2 = 360; lev = 18 ; variables: float V(lev,d0,d1,d2) ; T:long_name = "Precipitable Water" ; T:units = "cm" ; T:coordinates = "lon lat" ; float lev(lev) ; lev:long_name = "pressure level" ; lev:units = "hPa" ; float lon(d0,d1,d2) ; lon:long_name = "longitude" ; lon:units = "degrees_east" ; float lat(d0,d1,d2) ; lat:long_name = "latitude" ; lat:units = "degrees_north" ; --- My question is, should lat / lon coordinate variables be always 2-D array in CF-convention for two dimensional coordinate system? Thanks, -- +1(217)265-7710 http://hdfeos.org ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata ___ CF-metadata mailing list CF-metadata@cgd.ucar.edu http://mailman.cgd.ucar.edu/mailman/listinfo/cf-metadata
