Changes between Initial Version and Version 2 of Ticket #151


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Timestamp:
07/04/16 05:34:37 (3 years ago)
Author:
martin.juckes
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  • Ticket #151 – Description

    initial v2  
    11The CF standard name `region` has the current description "A variable with the standard name of region contains strings which indicate geographical regions. These strings must be chosen from the standard region list." This description implies that the variable should be of character type, but it is often more convenient to have an integer variable and make a clear link to the region names using `flag_values` and `flag_meanings`. The proposal is to clarify the definition so that either usage is acceptable and include an example of the latter usage in the convention text. It is also proposed that an appendix be added to the CF Convention text to state clearly any constraints on file meta-data which are implied by the CF Standard Name definitions, so that it is possible to test such constraints in the CF checker.
    22
    3 == New description for CF standard name "region" ==
     3== New descriptions for CF standard names ==
    44
    5 A variable with the standard name of region must have values associated with geographical regions from the CF standard region list, either as a character variable using the region names directly or as an integer variable with values linked to region names through flag_values and flag_meanings attributes.
     5=== region ===
     6
     7A variable with the `standard_name` of `region` contains strings which indicate a geographical region or integers which can be translated to strings using `flag_values` and `flag_meanings` attributes. These strings are standardised. Values must be taken from the CF standard region list.
     8
     9=== area_type ===
     10
     11A variable with the `standard_name` of `area_type` contains strings which indicate the nature of the surface e.g. land, sea, sea_ice, or integers which can be translated to strings using `flag_values` and `flag_meanings` attributes. These strings are standardised. Values must be taken from the area_type table.
    612
    713== New usage example in CF Convention text ==
    814''The following should be placed at the end of 6.1.1, after example 6.2''
    915
    10 A variable with standard name 'region' may also be of integer type and use 'flag_values' and 'flag_meanings' attributes to express the relationship between the integers and the region names:
     16A variable with standard name of `region`, `area_type` or any other standard name which requires string-valued values from a defined list may alternatively be of integer type and use `flag_values` and `flag_meanings` attributes to record the translation between the integers and the string values, for instance:
    1117
    1218{{{
    13 integer basin(basin);
     19int basin(lat, lon);
    1420       standard_name: region;
    1521       flag_values: '1 2 3';
     
    1723......
    1824values::
    19    basin: 1, 2, 3;
     25   basin: 1, 1, 1, 1, 2, .....
    2026}}}
    2127 
     
    3339B.2.1: region
    3440
    35 Variables with standard name '''region''' must be one of:
     41Variables with standard name `region` must be one of:
    3642 * type character, with values taken from the CF standard region list;
    3743 * type integer, with `flag_values` and `flag_meanings` attributes. The flag_meanings attributes must be a space separatd list of values from the CF standard region list (see example 6.2).
    3844
     45Variables with standard name `area_type` must be one of:
     46 * type character, with values taken from the area type table;
     47 * type integer, with `flag_values` and `flag_meanings` attributes. The flag_meanings attributes must be a space separatd list of values from the area type table (analogous to example 6.2).
    3948
    4049
    41