# Earthworm Module:
Sgram Overview

(last revised 18 October, 1999)

### Sgram - Spectrogram displays for the WWW

A few initial caveats: The present version is Solaris only. An NT version will be produced.

Sgram is designed to rapidly provide GIF images of spectrograms for display on the WWW. Sgram periodically retrieves current data for a selected list of stations and updates GIF images which are transferred to webserver(s). The required waveforms are obtained via periodic requests to Earthworm waveserver(s). Spectra are computed, converted to a color scale and plotted directly to GIF format image files. As the required GIF files are constructed, they are copied via rcp to webserver(s) for viewing. Perl Scripts are used on the webserver(s) to dress up the data displays. Optionally, .html wrappers may be built and copied via rcp to the webserver(s) for viewing.

The optional structure for the webserver consists of an index.html page listing the stations and dates available for viewing. The dates are each a hotlink to a station/date spectrogram GIF.

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