The Eric system provides users with an HTML form that can be used to request particular information products from the database of satellite imagery. A sequence of forms is used to narrow down the particular options relevant to a hierarchy of choices presented to the user. At each stage, the HTML form presented to the user has links to help information and to the main menu of Eric options. Data is delivered back to the user directly as an embedded image or movie or text file. Eric's product cache.
Single image results screen.
In the case of popular products and for a system that may be serving a large community of users, there is a potential performance improvement in managing caches of final and intermediate products. Our system does this by using a data oriented naming scheme that can be parsed at any stage by the driver script. For computationally intensive operations, this makes it possible to determine whether the result has already been computed and is in the cache. Our present system uses a simple naming scheme based on adding many details to the filenames used - a more robust server based database approach would be preferable since it would allow better organisation of the cached data than a flat file structure. The present Eric system makes heavy use of temporary files to handle multiple user requests and to track the intermediate results between programs chained together to provide the various services Eric offers.