Changes between Version 37 and Version 40 of Ticket #142


Ignore:
Timestamp:
02/18/16 00:55:43 (4 years ago)
Author:
markh
Comment:

i have modified the proposal addressing the majority of the points raised by jonathan

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  • Ticket #142 – Description

    v37 v40  
    1717== 4. Technical Proposal ==
    1818
    19     ==== 4.6 Ensemble Coordinate ====
     19    ==== 4. Coordinate Types ====
     20
     21    ... The attribute axis may be attached to a coordinate variable **or auxiliary coordinate variable** and given one of the values X, Y, Z**,** ~~or~~ T **. These labels** ~~which~~ stand for a longitude, latitude, vertical, ~~or~~ time **or ensemble** axis respectively. ...
     22
     23    ==== 4.6 Ensemble Axis ====
    2024
    2125    Variables representing an ensemble or collection of realizations shall have an attribute `axis` with a value `E`.  These variables are discrete, as described in section 4.5;  they do not represent continuous quantities.
    2226
    23     Ensemble variables have a number of optional standardised attributes available for use.  Further bespoke attributes to describe the ensemble in project specific ways are always allowed.
    24 
    25     ===== 4.6.1 Identifying Members =====
     27    Ensemble variables have a number of optional standardised attributes available for use.
    2628
    2729    A data variable representing an ensemble will commonly have an ensemble coordinate with the standard name `realization`; this is not mandatory. The `realization` standard name is used to provide a unique identifying number to each ensemble member within the ensemble.
    2830
    29     An ensemble coordinate providing a string label for each ensemble member within the ensemble may also be included.  The standard name `ensemble_member_label` is proposed (canonical unit = '' (string expected)); this name is not yet approved as a standard_name.  An `ensemble_member_label` shall have unique values and missing values are not allowed.
    30 
    31     ===== 4.6.2  Ensemble Control Member ====
     31    An ensemble coordinate providing a string label for each ensemble member within the ensemble may also be included, using the standard name `ensemble_member_label`.  An `ensemble_member_label` coordinate shall have unique values and missing values are not allowed.
    3232
    3333    An ensemble coordinate with the standard name `realization` or `ensemble_member_label` may include an attribute named `ensemble_control_member`.
     
    3535    This value provides a definition that one member of the ensemble is the control member and identifies this member.  This control member shall have the identified value within the ensemble coordinate's data.
    3636
    37     The absence of this attribute shall be interpreted as a negative statement, explicitly stating that there is no control member identified within the ensemble.
    38 
    39     ==== 4.6.3 Single or Multiple Model Ensemble  =====
     37    The absence of this attribute shall be interpreted as a negative statement, explicitly stating that there is no control member identified within the ensemble: all members have equal status, no control member existed in the ensemble.
    4038
    4139    An ensemble coordinate may be identified as being from one model or multiple models by providing further variables identified as coordinates or auxiliary coordinates by the data variable.  All of these coordinates shall have an attribute `axis` with a value `E`.