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Paper: Chapter 50: How to Build Client Applications with VOClient
Volume: 382, The National Virtual Observatory: Tools and Techniques for Astronomical Research
Page: 545
Authors: Tody, D.; Fitzpatrick, M.J.
Abstract: VOClient is a software facility which runs locally on a user‛s computer, implementing the client side of the major VO data-related services. VOClient handles the details required to connect to the VO, execute remote services, and discover and download data. The downloaded data is cached locally for high performance data access, and a high level API is provided to gain access to the data at various levels. Bindings of the VOClient functionality are provided for most major compiled and scripting languages and astronomical environments. VOClient currently supports VO registry queries, plus the simple cone search (SCS) and simple image access (SIA) interfaces for access to catalog and image data. Support for access to spectral data is expected in mid-2007, and support for other forms of astronomical data will be added as standard VO data access layer (DAL) protocols for additional types of data become available. An overview of the VOClient facility is given in Chapter 22. In this chapter we illustrate how to use VOClient to implement simple cone search and simple image access client applications. Any application which uses VOClient will follow the same pattern as the examples shown here, as all data interfaces share the same form. To illustrate the multi-language nature of VOClient, we will implement our sample programs in both Java and C; however, these sample programs could be implemented in any of the supported languages with the same results. Translation to other languages is straightforward, as the VOClient API is much the same in all supported languages.
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