INSPIRE WS2 METADATA: Describing GeoSpatial Data

Transcription

1 WS2 METADATA: Describing GeoSpatial Data Susana Fontano

2 Planning General concepts about metadata The use of standards Items about the creation of metadata Software How to create metadata The ISO19115 Standard Metadata IDENA Profile Practical exercises (show the results with style sheets)

3 General Concepts There is a real need to document the data for future use. Data without context are not as valuable as documented data. There are three principal problems: Poor knowledge of existing data. Poorly documented information about the data. Data inconsistencies.

4 General Concepts Metadata is useful for all data users (city planners, graduate students in geography, forest managers ), but they also benefit from the creator of the data by maintaining the value of the data and assuring their continued use over a number of years.

5 General Concepts Metadata means data about data, and is the term used to describe the summary information or characteristics of a set of data. Metadata are used not only to describe spatial data, but they can also describe medication, printed maps, library catalogues. Metadata answer the terms: what, who, where, why, when and how of the data.

6 General Concepts Benefits of metadata: MD help users to find the data they need and determine how best to use it. MD benefit the data producer organisation. Not duplication of efforts. Nowadays, the organizations starts to recognize the value of this information and they often begin to look at incorporating the metadata collection within the data management process.

7 General Concepts There are different levels of metadata: Discovery metadata Exploration metadata Exploitation metadata Each of these purposes require different levels of information.

8 General Concepts Discovery metadata: Is the minimum amount of information. They have to answer the following questions (broad categories): What: title and description Why: abstract detailing reasons for the data collection and its uses When: when the data set was created and the update cycles, if any. Who: originator, data supplier Where: the geographical extent (in coordinates, geographical names or administrative areas) How: how it was made and how to access the data.

9 General Concepts These broad categories are only a few in number to reduce the effort of collecting the information. The level of the metadata detail that will be documented depends on: the type of data held the methods that it is accessing and using the scope of the data being defined

10 General Concepts Exploration metadata: After discovery, more detail is needed about individual data sets. Provides sufficient information to ascertain that data fit for a given purpose. Reference some point of contact for more information. Include those properties required to allow the prospective end user to know whether the data will meet general requirements or a given problem.

11 General Concepts Exploitation metadata: Include those properties required to access, transfer, load, interpret and apply the data in the end application where it is exploited. This class of metadata often includes the details of a data dictionary, the data organisation, projection and geometric characteristics and other parameters that are useful in the proper use of the geospatial data.

12 The use of standards Metadata should be referenced to a standard. Why? Because whithout standardization, meanful comparisons are more difficult to derive. Standards have been developed through a consultative process (experts). Software programs will be developed to implement the standard. Problem: there are a number of standards in use or development.

13 The use of standards The three main standards are: FGDC CEN ISO The Content Standard for Digital Geospatial Metadata Adopted in 1994, revised in 1998 FGDC: Federal Geographic Data Committee U.S., Canada, United Kingdom, Latin American, Asia... ications/index_html

14 The use of standards The CEN Pre-standard Adopted in 1998 Comité Européen de Normalisation In 2003 address the development of European profiles of ISO TC 211 standards.

15 The use of standards The ISO (International Standard) Approved in 2003 ISO TC CatalogueDetail?CSNUMBER=26020&ICS1= 35 ISO (Draft Technical Specification), standarises the expression of metadata using the Extensible Markup Language (XML) and includes the logical model (UML) derived from ISO Currently under development.

16 The use of standards OpenGeospatial Abstract Specification (OGC: OpenGeospatial Consortium) consider metadata too, and has adopted ISO as the abstract model for metadata management within the consortium.

17 The use of standards Another standard not specific to geospatial information: Dublin Core This standard is centraliced around a core element set. DC metadata is specifically intended to support general-purpose resource discovery.

18 Items about creation of metadata Who? The creator of metadata needs to know information about the data in order to document them. Two options: creator of data = creator of metadata another person... In this case a good communication there is necessary between the data producer and the metadata producer.

19 Items about creation of metadata Factors related to the maintainance of metadata: the size of the data the size of an organisation the patterns of data management Principal inconvenients: It is too hard Insufficient time Solutions: Consider the interest and availability of the organisation

20 Items about creation of metadata Advice: Minimum metadata (choose the correct level) Specific software to fill in the metadata (less time and effort) Do not invent your own standard Use metadata tools Make your own profile Interoperability (IDE)

21 Items about creation of metadata Metadata Format (XML): Is widely accepted for international software support (free and commercial) Is the format to exchange metadata XML + XSL Presentation of metadata for users Allow change tag names, show only certain fields of information

22 Software There are several tools to create metadata with, according to different standards. Esri metadata editor uses different standards (FGDC, ISO19115) At national level in Spain there is the CatMdedit (used for the IDEE) At a regional and thematic level, different organizations have developed their own programmes: MetaD or IME.

23 Software The software we use is CatMdedit, but at the beginning we used ArcCatalog. Advantages for our company to use Catmdedit: Is the tool used by the IDEE (more interoperability and the same advancement) Implements the last version of the ISO19115 standard Has thesaurus implemented Has the majority of the ISO19115 metadata elements Has the IDEE profile (similar to us)

24 How to create metadata Process: Define exactly what data is to be documented. Assemble information about the data. Create a digital file (xml) containing the information (with an appropiate software). Review the content of the metadata.

25 How to create metadata Some years ago our organization realized the importance of metadata We had lots of data, and almost no information about theirs!!! The beginning: Make a list of all data in the GIS department (SITNA) Establish methodology Establish the standards and profile to use Complete the metadata we know Invest in the metadata we do not know

26 How to create metadata The dificulties: Establish our profile of metadata: it was not as easy as we thought. Invest in metadata we don t know: sometimes nobody remembers about the origin of data, or about their process of construction and, in some cases, we do not know the propieter!

27 How to create metadata The results: The beginning was difficult, a lot of previous tasks. Now we have all our data documented. The medatada are maintained regularly. When new data is introduced in some systems (SITNA, IDENA, IDEPAMPLONA), we create the medatada inmediatly.

28 The ISO19115 Metadata Standard Principal metadata standard of Europe. It consists of 300 metadata elements ISO Core is the nucleus (most important metadata) It is possible to create profiles (to satisfy the organizational needs).

29 IDENA Profile This is based in the NEM (Spanish nucleus of metadata). To assemble the most important metadata for our organization. The need to establish profiles (300 elements in ISO19115 standard, 42 in IDENA profile). It is used for IDEPamplona too.

30 IDENA Profile Consists of: Core ISO (ISO19115) Dublin Core Quality elements NEM Additional elements IDENA Additional elements

31 IDENA Profile Core ISO (22 elements = 7 mandatory and 15 opcional) Dataset title (M) Dataset reference date(m) Reference system(o) Dataset responsible party(o) Lineage(O) Geographic location of the dataset (by four coordinates or by geographic identifier) (C) On-line resource (O) Dataset language (M) Dataset character set(c) Dataset topic category (M) Spatial resolution of the dataset (O) Abstract describing the dataset (M) Distribution format (O) Additional extent information for the dataset (vertical and temporal) (O) Spatial representation type (O) Metadata date stamp (M) Metadata file identifier (O) Metadata standard name (O) Metadata standard version(o) Metadata language (C) Metadata character set (C) Metadata point of contact (M)

32 IDENA Profile Dublin Core elements (4): Contributor Relation Rights management Type NEM additional elements (4): Keywords (theme and place) Type of presentation Use Purpose

33 IDENA Profile Quality elements (3-6): Statement Hierarchical level Type of quality control IDENA aditional elements: Alternative title Father identifier Frequency of maintenance State Suplementary information Distribution information

34 IDENA Profile 22 ISO Core elements 4 Dublin Core elements 6 Quality elements 4 NEM Additional elements 6 IDENA Additional elements NEM Alternative title Father identifier Frequency of maintenance/update Suplementary information Distribution State

35 IDENA Profile NEM ISO19115 Dublin Core Quality ISO Core Additional Elements IDENA PROFILE (NEM + Additional Elements)

36 Practical exercise ArcCatalog metadata editor

37 CatMdedit Practical exercise

38 Practical exercise We are going to create three metadata files: Ortophotography of Navarre Health zonning Hydrography network

39 Practical exercise Documents (HTML) XSL Metadata Search O.G.C. Catalogue Metadata Administrator IDENA profile ArcCatalog CatMdEdit XML Metadata Repository Conversion