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-----BEGIN PGP SIGNED MESSAGE----- Hash: SHA1 Hi, At the danish and swedish meteorolical institutes, we have implemented the prototype suggestion. We have two points we would like to discuss here: - - Wavelength: we find it necessary to add the minimum and maximum wavelength (spectral range) to the metadata. We think it is not enough just to specify one wavelength for a band. - - Geolocalization: we have quite a lot of data that is easily represented on a grid, but the CF-convention requires the grid of lons and lats to be calculated. This is of course highly inconvenient for fixed grids (from a data storage and transfer perspective). We suggest adding a proj-string (proj.4 string definition) and an area-extent option in the convention for grids. To us, it makes a lot more sense than maintaining a list of accepted pre-defined grids in the convention. Best regards, Martin Raspaud, Adam Dybbroe (SMHI) Esben Stigård Nielsen, Kristian Rune Larsen, Lars Ørum Rasmussen (DMI) Tom Whittaker skrev: > We would like to suggest the following as a "starting point" that we > can refine toward the goal of agreeing on a "basic" set of metadata > and structure. It is an example of a multi-banded image structure > that contains navigation on a point-by-point basis, and provides for > linear calibration. The variable "names" are not critical, but the > "standard_name" should be used by applications to identify the > quantity. > > (In the following, most of the numbers are just samples....to make it > more readable...) > > dimensions: > x = 5304 ; > y = 2438 ; > band=16 > > variables: > float lat(y, x); > lat:standard_name = "latitude" ; > lat:units = "degrees_north" ; > lat:valid_range = -90.f, 90.f ; > > float lon(y, x) ; > lon:standard_name = "longitude" ; > lon:units = "degrees_east" ; > lon:valid_range = -180.f, 180.f ; > > int band(band); > > double time; > time:long_name = "Nominal time of image"; > time:units="s since 1990-1-1 0:0:0"; > > string bandname(band); > bandname:standard_name = "band_name" ; > > float offset(band) ; > offset:standard_name="linear_calibration_offset"; > > float scale(band) ; > scale:standard_name="linear_calibration_scale_factor"; > > float wavelength(band); > wavelength:standard_name="radiation_wavelength"; > wavelength:units="micron"; > > string units(band); > units:standard_name="band_units"; > > short ImageData(band, y, x) ; > ImageData:coordinates = "band lat lon" ; > ImageData:valid_min = 1s ; > ImageData:_FillValue = 0s ; > ImageData:missing_value = 0s ; > > and for people who want/need to use a table look-up for calibration -- > instead of the "linear_calibration..." > variables, we would use: > > float lookup(band, 256); > lookup:standard_name="calibration_lookup_table"; > > > As Russ Rew pointed out, if there is only one band, it would be > possible to dimension the Data as (y,x) but have the coordinates > attribute contain "band". > > > tom > (with help from Tom Rink and Kaba Bah) > -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.9 (GNU/Linux) Comment: Using GnuPG with Fedora - http://enigmail.mozdev.org/ iQEcBAEBAgAGBQJMc2/IAAoJEBdvyODiyJI4w0wIAIw5QsZO9r3qmDnZLCz1ot7h +ws9qbrxklIfIxN7vuaSxTedonv++ulc9E90LVqyxKcOn/e8GM5XGSREjw8CAVhk 8PynsvvfHnjI5y3yZchoIy/znIt7bgTtGtTA6Ll+zgk3M5QxuFSC+jonfLk1EWzJ KFR6+Vtb64aztmBFYaKkvvOyUC0Xr/kVX7y+5K4sclHbQQaOSxO67yX1BdpWWPAX hXWWuLuLUZQNNwzi5o6FgQ2jom4mUxhZu/xbjeSl4fyehCgcw1TnE9BQ1aikTSaZ dIxTGI7gbHNARglIp2f7npaR6/yvCx5jQKf5SqgHQBSmyG2TTmzsxbokLACrsd8= =w/WO -----END PGP SIGNATURE-----
begin:vcard fn:Martin Raspaud n:Raspaud;Martin org:SMHI adr;quoted-printable:;;;Norrk=C3=B6ping;;60176;Sweden email;internet:martin.raspaud@xxxxxxx tel;work:+46 (0)11 495 8261 tel;cell:+46 (0)11 495 8261 x-mozilla-html:FALSE version:2.1 end:vcard
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