WORLD
METEOROLOGICAL ORGANIZATION |
ET-IDM/Doc.
3(1) |
Proposal for a Discovery-level WMO Metadata Standard
Submitted by the Secretariat
Summary and Purpose of Document The following straw-man proposal, based on the Global Change Master Directory DIF (Directory Interchange Format), the WMO BUFR code tables and the emerging ISO metadata standard defines basic descriptive or directory-level metadata that should be made available and searchable. |
ACTION PROPOSED
The meeting is requested to consider the proposal and provide suggestions for further development and follow-up actions.
Discussion
The wide range of data and products that could be of potential use to the various WMO programmes creates a need for extensive metadata to describe them. Furthermore, to facilitate identification and location of this information across a number of programmes, basic descriptive or directory-level metadata should be made available and searchable according to an agreed standard. It is important that the extent of this directory-level information be detailed enough to provide critical information but simple enough to be easily collected and maintained. The following proposal, based on the Global Change Master Directory DIF (Directory Interchange Format), the WMO BUFR code tables, and the draft ISO metadata standard attempts to provide the appropriate balance.
All of the fields below would be required. The proposed standard would provide a definition for directory searches and would not specify how the information should be archived or presented to users.
Field |
Field contents |
Field definition |
Abstract |
Character string |
Brief narrative summary of the contents of the dataset |
MD_Keywords |
Character string |
Keywords, their type and reference source (WMO) |
Language |
Code, ISO 639 |
Language of the description |
StartDate |
Date, ISO 19108 |
Beginning or actual date of the data |
StartTime |
Time, UTC |
Beginning time of the data (UTC) |
StopDate |
Date, ISO 19108 |
Ending date of the data (blank if not applicable) |
StopTime |
Time, UTC |
Ending time of the data (blank if not applicable) |
ReferenceDate |
Date, ISO 19108 |
Reference date of the dataset (blank if not applicable) |
ReferenceTime |
Time, UTC |
Reference time of the dataset (blank if not applicable) |
Geographic |
Angle (-180 to 180)Angle Angle Angle |
WestBoundLongitude EastBoundLongitude NorthBoundLatitude SouthBoundLatitude |
Geographic Description: |
CharacterString |
Geographic Identifiers (ISO 19112) |
MD_Category |
Code |
Numeric code for the discipline
covered by this dataset See ISO standard below |
Theme |
Code |
The theme or subject of the dataset would be specified from a list of standard themes defined for each category. A very rough first draft is given below. |
MD_Category
Name | Code | Definition |
Agriculture / Farming | 001 | Agriculture, herding, irrigation, plantations |
Climatology / Meteorology / Atmosphere | 005 | Processes and phenomena of the atmosphere (cloud cover, precipitation, temperature); changes in climate |
Elevation and derived products | 008 | Altitude (elevation, height above or below sea level) |
Geoscientific information | 010 | geography (topography, toponomy); geomorphology; general geology; economic geology; geophysics; soils; geochemistry; permafrost; geological processes; palaeontology; risks of earthquakes, volcanoes, sinkholes, landslides, avalanches |
Imagery / Base maps / Earth cover | 012 | remotely sensed information such as ground cover e.g. scans of the earth by satellite, aerial photographs and imagery; topographic maps, aeronautical, topocadastral maps, hydrographic charts; land use (land cover, public lands, land tenure, urban and regional land use plans) |
Inland waters | 014 | rivers, lakes, glaciers, continental ice sheets, snow; ground water; water utilisation plans; movement of water in relation to land; floods; dams; pans; vleis; swamps; reservoirs; marshes; drainage regions; swimming pools |
Oceans | 017 | Salt water bodies and their features; bathymetry, tides, currents, waves, nautical aides |
Dataset Themes (Subsets of Categories)
Agriculture (001)
Climate / Meteorology / Atmosphere (005)
Elevation and derived products (008)
|
Geoscientific information (010)
Imagery / Base maps / Earth cover (012)
Inland waters (014)
Oceans (016)
|
Sample Entry in a Metadata File
The sample provides an example of a dataset description conforming to the proposed guidelines. However, The ISO standard defines the content of a set of metadata elements, their definitions, data types, and inherent dependencies. The logical model of the metadata specifies the content and not the form of implementation or the form of presentation. A primary goal in the management of geographic metadata is the ability to access the metadata and the related spatial data it describes. This requires software implementations using common encoding methods to achieve operational use of the geographic metadata. Annex I to the ISO standard provides an overview of methods for the encoding of metadata element structure and content for the purposes of search and retrieval, metadata exchange, and presentation.
The example below includes item tags and indentation to aid interpretation but does not represent a recommended presentation. Instead the metadata should be presented encoded in Standard Generalised Markup Language (SGML), eXtensible Markup Language (XML) or in another agreed presentation format.
hierarchyLevel: dataset
identificationInfo
MD_Identification
language: en
characterSet: ISO 10646-2
abstract: NCAR provides European Center for Medium Range Weather Forecasting FGGE global analysis data. This is a gridded analysis of data on a horizontal surface. Grid coverage includes the entire globe (uniform and complete latitude/longitude grid, 96x25, 3.75-degr, northern hemsiphere and southernhemisphere are separate, derived from 192x49 1.875-degr).
MD_Keywords:
keyword: grid, analysis, global, surface,1000mb, 850mb, 700mb, 500mb, 400mb, 300mb, 200mb, 150mb, 100mb, 50mb, 30mb, 20mb, 10mb
type: 001 (vertical/spatial)
thesaurusName: WMO
keyword: {appropriate GRIB parameter codes, 001, 006, 011, 017, etc}
type: 002 (GRIB parameters)
thesaurusName: WMO
geographicBox:
westBoundLongitude: -180.0
eastBoundLongitude: 180.0
northBoundLatitude: 90.0
southBoundLatitude: -90.0
geographicDescription
SI_LocationInstance
geographicIdentifier: Globe
EX_TemporalExtent
startDate: 19781201
startTime: 0000
stopDate: 19791130
stopTime: 2359
MD_Category: 005
Theme: Model analyses, Temperature, Water Vapour, Wind
CI_Citation
title: ECMWF FGGE global analysis
date: 19970801
dateType: publication date
edition: 1
datasetPointOfContact:
CI_ResponsibleParty
organisationName: NCAR Data Support Section
CI_Telephone
voice: 1-(303) 497-1219
facimile: 1-303-497-1298CI_Address
deliveryPoint: NCAR/SCD/Data Support Section, P.O. Box 3000
city: Boulder
administrativeArea: CO
postalCode: 80307
country: USA
electronicMailAddress: datahelp@ncar.ucar.eduCI_OnlineResource
linkage: http://www.scd.ucar.edu/dss/datasets/ds307.5.html