TIN:: An interactive image navigator providing ubiquitous access to distributed geo-spatial data

In this paper we describe the design of the TerraScope Image Navigator (TIN), the graphical user interface module of the TerraScope system. TerraScope is an earth science data middleware system that was designed to facilitate collaboration among a set of data repositories (peers) who wish to provide their geospatial data thru an integrated portal. The base of the system is a distributed database that collects heterogeneous spatial data taken from satellite ground stations. TIN, as a component of TerraScope, retrieves images and related information from the distributed database and deals with the effective presentation of this kind of data to the user. TIN allows recursive navigation of the image space by dynamically embedding retrieved sub images as spatial hyperlinks inside other retrieved images. The TIN prototype was implemented using an interactive movie authoring environment (Flash MX) and XML (eXtensible Markup Language) to communicate queries and retrieve data and metadata from the server. As a result, we expect to port TIN to multiple platforms, including portable devices, with relative ease. Measurements using a small image database suggest result set rendering times in the order of a few seconds and response time 97% dominated by server computation.