Difference between revisions of "CSN Metadata Names"

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<h2 style="margin:4px; background:#DCD0FF; font-size:150%; font-weight:bold; border:1px solid #aaa; text-align:left; color:#000; padding:0.2em 0.4em;"> Model Metadata File (MMF) Tags </h2>
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* Every model submitted to CSDMS should include its own Model Metadata File (MMF), which is an XML file with a small number of standard tags as defined here. <br/> <br/>
 
* Every model submitted to CSDMS should include its own Model Metadata File (MMF), which is an XML file with a small number of standard tags as defined here. <br/> <br/>

Revision as of 11:55, 16 August 2012

  CSDMS Standard Names — Metadata Names

  • CSDMS Standard Names follow the pattern:
[ operation ] + object + quantity

These standard names are used as keys or indices that are used to access values, as well as associated metadata. The values (data) will often be accessed from memory, while the metadata will (most likely) be accessed from a Model Metadata File (MMF). This document decribes MMF files and provides standardized strings to be used within them.

  • Assumptions, conditions and explanations are not included in the construction of CSDMS Standard Names, even though this is allowed in CF Standard Names. There are at least 3 reasons for this:
(1) When an automated system is trying to match variables (i.e. users to providers) in
    two different entities (e.g. models or databases), the assumption part of the name
    may prevent matches that we would want to allow, at least initially.  We expect
    that the system will use the metadata to provide a user with details (or warnings)
    on how "good" a given match is.  For example,

    channel_water_speed  vs.
        channel_water_speed_assuming_diffusive_wave 
        channel_water_speed_assuming_kinematic_wave
  
(2) We want to encourage model developers and database providers to list any and all
    assumptions that may be relevant in attached metadata (e.g., an RDF file).  We are
    expecting that each user of a given standard name should provide an RDF file with
    metadata that describes how they interpret and use the name.  This includes units,
    how measured (e.g. an angle could be CCW from north;  an elevation could be relative
    to a datum, etc.) reference ellipsoid name, datums, model name and so on.
  
(3) Standard names that include many assumptions will become long and unwieldy.
    An otherwise valid match may be broken simply because one person provides a
    more complete list of assumptions.  
  • CSDMS promotes a "check all that apply" approach where XML tags such as <assumption> and <how_modeled> can be used numerous times to describe a model in detail. For example, a fluid dynamics model could list "navier_stokes_equation" and "reynolds_averaged" with two different instances of the <how_modeled> tag. In addition, "newtonian_fluid" and "compressible_fluid" could be listed with two <assumption> tags.)


Model Metadata File (MMF) Tags

  • Every model submitted to CSDMS should include its own Model Metadata File (MMF), which is an XML file with a small number of standard tags as defined here.

  • MMF files should begin with a <model> tag. The MMF construction could be extended to databases and perhaps called DMF files. DMF files would begin with a tag and would have <output_var_name> tags but no <input_var_name> tags.

  • The placement of these XML tags determines their scope. For example, if an <assumption> tag is used within a <model> block but outside of any <input_var_name> or <output_var_name> block, then that assumption is understood as applying to the model as a whole. (For example: <assumption>conserves_mass</assumption>.) When used within an <input_var_name> or <output_var_name> block, an <assumption> tag is understood to apply only to that variable. Similarly, an <ellipsoid> tag can be applied to an entire model or to a particular input or output variable.

  • Note that within a BMI-enabled model, CSDMS Standard Names are used as arguments to several of the BMI methods and in some cases as dictionary keys (e.g. python dictionaries). An MMF file may be read for the (automatic) implementation of some BMI getter methods that take "long_var_name" as an argument.

  • The <model> tag. An MMF file should begin with this tag.

  • <input_var_name> tags. An MMF file must contain one of these tags for every input variable that the model wants to be able to retrieve from other components. The first thing provided in an <input_var_name> block is a complete CSDMS Standard Name. Following the standard name, the block should contain additional, nested XML tags to provide information about how the variable is used by the model such as <units>, any number of <assumption> tags, an optional <how_modeled> tag, and so on as explained below.

  • <output_var_name> tags. An MMF file must contain one of these tags for every output variable that the model wants to be able to provide to other components. As with the <input_var_name> tag, nested XML tags provide additional information.

  • <assumption> tags.

  • <units> tags.

  • <how_modeled> tags.

  • <how_measured> tags. This is the analog to the <how_modeled> tag but only applies to Database Metadata Files (DMF) files.


Assumption Names


Units Names



Ellipsoid Names

Airy_1830
Airy_Modified_1849
Australian_National_Spheroid
Average_Terrestrial_System_1977
Bessel_1841
Bessel_Modified
Bessel_Namibia_GLM
CGCS2000
Clarke_1858
Clarke_1866
Clarke_1866_Authalic_Sphere
Clarke_1866_Michigan
Clarke_1880
Clarke_1880_Arc
Clarke_1880_Benoit
Clarke_1880_IGN
Clarke_1880_International_Foot
Clarke_1880_RGS
Clarke_1880_SGA_1922
Danish_1876
Everest_1830_1937_Adjustment
Everest_1830_1962_Definition
Everest_1830_1967_Definition
Everest_1830_1975_Definition
Everest_1830_Definition
Everest_1830_Modified
Everest_1830_RSO_1969
GEM_10C
GRS_1967
GRS_1967_Modified
GRS_1980
GRS_1980_Authalic_Sphere
Helmert_1906
Hough_1960
Hughes_1980
IAG_1975
Indonesian_National_Spheroid
International_1924
International_1924_Authalic_Sphere
Krassowsky_1940
NWL_9D
OSU86F
OSU91A
Plessis_1817
PZ-90
Struve_1860
War_Office
WGS_72
WGS_84


Datum Names


Projection Names