SAHRA Metadata Guidelines

Transcription

1 SAHRA etadata Guidelines What are etadata? etadata are data or information about data which are usually stored in a structured document. etadata describe the origin, nature, and spatial and temporal location of data. They are important in searching, sharing and using the data in scientific communities. A metadata document consists of elements which guide its creation and facilitate the search and retrieval process of data. etadata elements are arranged in a metadata model or schema and described using worldwide standards: International Standard rganization (IS) 19115:2003 ( Federal Geographic Data ommittee (FGD) STD ( Dublin ore ( Scientific communities often develop more specific standards based on IS or FGD but add elements specific to the discipline. Some standards for hydrologic data include: UAHSI etadata Profile ( Ecological arkup Language (EL) ( Geographical arkup Language (GL) ( USGS Hydrologic arkup Language (HYDRL) ( Earth Science arkup Language (ESL) ( Geospatial etadata Standard ontent Standard for Digital Geospatial etadata (SDG) FGD-STD provides a common set of terminology and definitions for digital geospatial data documentation. It is mainly used in the United States. Basic elements are organized into ten groups, seven of them major (1-7) and three minor (8-10): 1. Identification Information 2. Data Quality Information 3. Spatial Data rganization Information 4. Spatial Reference Information 5. Entity and Attribute Information 6. Distribution Information 7. etadata Reference Information 8. itation Information 9. Time Period Information 10. ontact Information

2 A detailed description of these groups is provided at Basic elements of a metadata document include: Dataset Title Attributes Purpose Access onstraints ontact Information itation Time Period of Dataset Status Spatial Domain Keywords Distribution etadata Reference The harmonization of the new IS and FGD geospatial metadata standards will produce a universal standard for geographical metadata IS for digital geographical data. This standard is currently in draft stage. UAHSI etadata Standard Table 1 shows the UAHSI metadata profile recently developed by Piasecki et al. (2005). It consists of 24 IS-based elements which describe geo-spatial data and three additional elements from other parts of the IS standard. The other essential component of metadata standards is a controlled vocabulary (V). Using V is beneficial for consistency in metadata creation, for searching and browsing metadata, and for matching other metadata by creating links between similar terms. The main objective of UAHSI s metadata profile was to create a V that is interoperable with already existing Vs.

3 Table 1 UAHSI metadata profile (Piasecki et al., 2005) ( mandatory, optional, and conditional) Element Dataset Title Dataset Reference Date Dataset Language Dataset Topic ategory Abstract (description of dataset) etadata Point of ontact etadata Date Stamp Distribution Format Dataset Responsible Party Additional Temporal Extent Information Lineage n-line Resource etadata Standard Name etadata Standard Version etadata Language Geographic Location (four coordinates) Geographic Location (geographic identifier) Dataset haracter Set etadata haracter Set Spatial Resolution of the Dataset Additional Vertical Extent Information Spatial Representation Type Reference System etadata File Identifier UAHSI-Thematic Keywords Dataset Legal onstraints Dataset Security onstraints Requirement IS UAHSI ore information about the UAHSI etadata Profile can be found at

4 inimum etadata Description IS/UAHSI and FGD standards are very complex and contain over 300 elements, all of them important in the data description. ust all of these elements be described? What if sufficient information is lacking? This issue can be solved by defining a minimum searchable metadata set, which is a subset of the mandatory elements. Table 2 compares minimum requirements for description sets by UAHSI (Piasecki et al., 2005) and by the Denver Summit etadata ore (discussed at for geographic data. Table 2 inimum metadata set requirements for UAHSI and Denver ore UAHSI Publisher Subject keyword Spatial overage Temporal overage Title of Data set Description Download link of data file Download of full metadata set File format/resource type File size Access control of permission Last successful update Denver ore riginator Theme keywords Place keywords Bounding coordinates Time period of content Title Abstract Purpose Resource description Geospatial data presentation form urrentness reference Language

5 SAHRA etadata reation and Editing To describe data correctly we have to understand what they represent and how they were obtained. Then we have to decide what tools should be used to create metadata, based in part on data format and software availability. The SAHRA Geo-Database uses ArcSDE as the spatial engine. The metadata and all spatial data (vector and raster), tabular data, and time series are stored in an racle database. Based on the database implementation, we recommend that ESRI FGD/IS and UAHSI metadata profiles be used to generate metadata files for data uploaded to SAHRA Geo-database. Under certain circumstances, metadata may be created using the minimum metadata profile. 1. GIS software - ArcGIS A metadata editor is a part of the Arcatalog. This editor incorporates IS and FGD editors and a viewer form. It is easy to use and the required elements are marked with an asterisk. ore detailed information about the ESRI Profile (extended FGD standard) is described at The implementation of IS standards is described in Example of IS etadata Wizard implemented in Arcatalog. (Elements marked with * are required.)

6 Example of FGD etadata Wizard implemented in Arcatalog. 2. Stand-alone or Internet-based metadata editors TKE ( - a Windows-based multilingual metadata entry and editing tool with the FGD-STD standard implemented. It is developed by the USGS. XTE ( a UNIX-based metadata editing tool with the FGD-STD standard implemented. It is also developed by USGS. 3at ( an Internet-based metadata tool that supports multilingual metadata entry and editing. etadata can be created using various metadata standards (FGD, IS, GILS, NBII) and other metadata standards can be added. A list of additional metadata tools is listed at or Reference Piasecki,., L. Bermudez, B. Beran, S. Islam, Y. hoi, X. Liang, and S. Jeong. (2005) Hydrologic etadata, in Hydrologic Information System Status Report, ed. by D. aidment, UAHSI, Web access