| A Brief Tutorial on Data Retrieval from IRIS/USGS GSN Stations Near-real-time data are available several ways: 1. LISS port connection. Stations which have reasonable-quality internet connections have LISS software running, sending SEED binary records over the internet near-real-time. LISS currently has 25 stations hooked up. The number of stations available via the LISS will certainly increase as we install new stations and as quality internet connections become available at existing sites. Internet bandwidth is a limiting factor when considering what channels are sent over the internet (continuous 1 sps vs. continuous 20 sps). The software for hooking up to the LISS is available; however, we are finishing up instructions for the software. 2. Autodrm. The autodrm currently stores data from several weeks old to the most recent data available via the LISS. Binary SEED data currently are available from the autodrm; GSE format data will be available soon. Below I've included a sample e-mail request for autodrm data:
The file will contain information about your request and each SEED record as a separate uuencoded segment. There are 3 SEED records in this example. If uudecode is run on the file incoming file (example_data in this example), only the first uuencoded file is read, since uuencode stops after reading the first END statement, skipping the rest of the file. To solve this program, a short C program was written that breaks the file down into separate uuencoded files so the data can be easily converted. The program is called uubreak and is in pub/software/asl at our anonymous ftp site. If you would prefer the data file be mailed to you, omit the lines beginning with FTP and INTER. 3. Direct login to station. Simply log into a station as user "seed," password "data." Type "h" to list the options available. The "k" option is appropriate for data retrieival using Kermit software with modem connection. Data are downloaded within the Kermit session. (WARNING: Do NOT attempt to pull data over the internet using the "k" option. The data are corrupted when the kermit option is used over the internet. This a problem with incompatibility between the operating system used at IRIS/USGS stations and the kermit software) The "v" option archives the data as files on disk (use this option when telneting into a station). The file names used for the archived data are based on the buffer type, channel, date, and time. To retrieve the archived file, ftp into the station as user "ftp," password "data." Please delete any data you archive (delete the files through ftp) to avoid possible problems with filling up the hard disk. The file naming convention is fairly straightforward. A typical file name would be CB971110.J25. Broken down, this would be:
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