Clarifications to the preamble of sections 4 and 5
|Reported by:||jonathan||Owned by:||davidhassell|
I have the honour of opening ticket number 100. In this ticket, Steve Hankin and I have a number of changes to propose to the text of section 5, with the intention of clarifying it, not changing what it means. Therefore this is a defect ticket, but please object if you think it is changing the meaning, or making it any less clear!
Replace this text in the first paragraph
A variable's spatiotemporal dimensions are used to locate data values in time and space. This is accomplished by associating these dimensions with the relevant set of latitude, longitude, vertical, and time coordinates.
A data variable's dimensions are used to locate data values in time and space or as a function of other independent variables. This is accomplished by associating these dimensions with the relevant set of latitude, longitude, vertical, time and any non-spatiotemporal coordinates.
These changes clarify that coordinate systems belong to data variables (rather than any other type of variable in a CF-netCDF file) and recognise the use of non-spatiotemporal dimensions.
Replace this text in the second paragraph
All of a variable's dimensions that are latitude, longitude, vertical, or time dimensions (see Section 1.2, "Terminology") must have corresponding coordinate variables, i.e., one-dimensional variables with the same name as the dimension
Any of a variable's dimensions that is an independently varying latitude, longitude, vertical, or time dimension (see Section 1.2, "Terminology") and that has a size greater than one must have a corresponding coordinate variable, i.e., a one-dimensional variable with the same name as the dimension
These changes remove the implication that spatiotemporal scalar coordinates might be prohibited, and allow for discrete axes (section 4.5, used extensively in section 9).
Replace this text in the third paragraph
All of a variable's spatiotemporal dimensions that are not latitude, longitude, vertical, or time dimensions are required to be associated with the relevant latitude, longitude, vertical, or time coordinates via the new coordinates attribute of the variable
Any longitude, latitude, vertical or time coordinate which depends on more than one spatiotemporal dimension must be identified by the coordinates attribute of the data variable.
This change is for clarity.
Replace this text in the fifth paragraph
The use of coordinate variables is required whenever they are applicable. That is, auxiliary coordinate variables may not be used as the only way to identify latitude and longitude coordinates that could be identified using coordinate variables.
If the longitude, latitude, vertical or time coordinate is multi-valued and varies in only one dimension, it is not permitted to store it as an auxiliary coordinate variable.
This change is for simplicity and clarity. The use of coordinate variables where applicable is already required by the second paragraph.
Append to the fifth paragraph
If the longitude, latitude, vertical or time coordinate is single-valued, it may be stored either as a coordinate variable with a dimension of size one, or as a scalar coordinate variable (Section 5.7).
This change recognises the use of spatiotemporal scalar coordinates.
Change History (9)
comment:4 Changed 4 years ago by jonathan
- Summary changed from Clarifications to the preamble of section 5 to Clarifications to the preamble of sections 4 and 5