Research Topics
Some of the research topics that we have or expect to encounter include:
- Preservation Metadata
- File Formats
- Time-Version Management
- Archival Repository Architecture
- Geospatial Web Services
- Spatial Databases
Preservation Metadata
In addition to incorporating metadata developed in accordance with the FGDC Content Standard for Digital Geospatial Metadata, the project will investigate the development of additional administrative, technical, and descriptive metadata elements for use in the archival process. One possible approach will involve implementation of the PREMIS (PREservation Metadata: Implementation Strategies) data dictionary for preservation metadata. The project will also investigate packaging of the combined metadata elements into METS (Metadata Encoding and Transmission Standard) records.
File Formats
A wide range of vector and image formats will be encountered in the project domain. In the case of vector content, nearly all data will occur in proprietary formats, notably the ESRI Shapefile, Coverage, and Geodatabase formats. The absence of an open, reliable option for vector content will pose a key challenge to the project. The use of Geography Markup Language 3.x application schema as an open, XML-based option for data storage will be investigated.
Time-Version Management
Many of the acquired resources--particularly county and municipal vector data--are updated on a routine basis. One project challenge will center on managing the relationships between these time-versioned objects. As it is assumed that individual versioned objects will wander from the original archive, repository-independent approaches to relationship management will be explored.
Archival Repository Architecture
The project will investigate the digital repository technical requirements of geospatial content; however, a new digital repository software environment will not be developed. The project will investigate the interplay of geospatial content with readily available digital repository software environments in order to learn whether specialized environments are required for geospatial content. Initially the DSpace digital repository software will be used. One or more other environments such as FEDORA (Flexible Extensible Digital Object and Repository Architecture) be explored in other project stages. There is a strong desire to develop the collection in a software-independent manner.
Geospatial Web Services
The project will investigate the use of emerging Open Geospatial Consortium specifications in the process of archive development. Potential applications include automated map atlas development using Web Map Service (WMS) and vector data capture using Web Feature Service (WFS). One project goal will be to contribute preservation and archive-development use cases to the development of GeoDRM (Geo Digital Rights Management) initiative, which will address rights-related access issues for both services and data files.
Spatial Databases
patial databases are increasingly used to store not just feature and attribute data but also additional information such as annotation, behaviors, relationships, and topology. The inability to export some of these elements into widely used vector formats limits the preservation options. In the target domain, the ESRI Geodatabase format is used extensively. The project will investigate methods of archiving spatial databases in both their entirety and as extracted components.