Chapter Seven | Context and Rationale | Organisational Approach | Implementation Approach
Chapter Seven: Other Services
Editor: Jeff DelaBeaujardiere, NASA
Note to Readers: As additional services are built on existing infrastructures, this chapter will include greater depth on the following:
- Definition of services (e.g. build on catalog service, online mapping, data access)
- Types of additional services that may exist in SDIs: (transformation, classification, authentication, GIS analysis, data fusion, custom symbolisation, collaboration, gazetteer, referral systems, knowledge base, project and experts directory, applications, algorithms, software directories)
- What are the organisational issues of implementing additional services?
- What existing software services may be present in your SDI?
- What standards may exist for supporting services in SDI?
Context and Rationale
The preceding chapters have discussed three types of services that are fundamental to any Spatial Data Infrastructure: data catalogs, online mapping, and access. A broad range of other geospatial services may exist in SDIs. Other services include, but are not limited to, coordinate transformation, classification, data authentication and validation, data analysis, data fusion, custom symbolisation, multi-person collaboration, gazetteers, processing algorithms, and service catalogs allowing discovery of required services.
The OpenGIS Service Architecture defines a number of categories of Geospatial Domain Services. The following fall under the rubric of Other Services in the context of this document:
- Feature Generalisation Services - Services that modify the cartographic characteristics of a feature or feature collection by simplifying its visualisation, while maintaining its salient elements - the spatial equivalent of simplification.
- Geospatial Information Extraction Services - Services supporting the extraction of feature and terrain information from remotely sensed and scanned images
- Geospatial Coordinate Transformation Services - Services for converting geospatial coordinates from one reference system to another
- Geospatial Annotation Services - Services to add ancillary information to an image or a feature in a Feature Collection (e.g., by way of a label, a hot link, or an entry of a property for a feature into a database) that augments or provides a more complete description.
- Image Manipulation Services - Services for manipulating images (resizing, changing color and contrast values, applying various filters, manipulating image resolution, etc.) and for conducting mathematical analyses of image characteristics (computing image histograms, convolutions, etc.).
- Feature Manipulation Services - Services that support creation, quality control methods, analysis, and display of feature collections of interest to an end user.
- Image Exploitation Services - Services required to support the photogrammetric analysis of remotely sensed and scanned imagery and the generation of reports and other products based on the results of the analysis.
- Geospatial Analysis Services - exploits information available in a Feature or Feature Collection to derive application-oriented quantitative results that are not available from the raw data itself.
- Image Geometry Model Services - Support using mathematical models of image geometries, that relate image positions to corresponding real-world (e.g., ground) positions.
- Geospatial Symbol Management Services - Services for management of symbol libraries.
- Image Synthesis Services - Services for creating or transforming images using computer-based spatial models, perspective transformations, and manipulations of image characteristics to improve visibility, sharpen resolution, and/or reduce the effects of cloud cover or haze.
- Image Understanding Services - Services that provide automated image change detection, registered image differencing, significance-of-difference analysis and display, and area-based and model-based differencing.
Omitted from the foregoing list are those service categories covered in earlier chapters: Geospatial Domain Access Services, Image Map Generation Services, and Geospatial Display Services.
While specific GIS software packages may offer one or more of the services discussed here in a proprietary fashion, there are few existing standards and protocols for providing geospatial domain services in an interoperable manner. The OpenGIS Service Architecture defines (See Chapter 2) what specific services are included in each service category, but that abstract specification provides no implementation details. Thus, this chapter is simply a placeholder for future implementation advice to be included when available.
Table of Contents
Chapter Seven | Context and Rationale | Organisational Approach | Implementation Approach