Frequently Answered Question

Question

I requested some data and got a file back that I can't read. What do I do with this file?

Answer

It is first necessary to identify what kind of file this is.

Look for an extension or suffix

Many times, a file will have a suffix on it, like .txt, to indicate the type of file. IRIS will typically send users these kinds of data:

File suffix Description
.seed, .dataless, .miniseed, .mseed, .dless Files in SEED format
.SAC, .sac SAC format
.SAC_ASCII SAC ASCII format
.tar This is a tar archive file that probably contains data or many data files. Use the tar command to unwrap them to your disk.
.tar.gz This is a tar archive file that has been gzipped. Use gunzip to decompress the file, followed by the tar command to unwrap the contents.
.zip This is a zip archive file. Use the unzip command to unwrap the contents.
.RESP,.resp An ASCII file containing instrument response information for stations

Use the file command

Unix systems have a file command that you can run against files. Sometimes the system can identify what kind it is:

% file ms_ascii.tar.gz
ms_ascii.tar.gz: gzip compressed data, from Unix

Contact IRIS DMC with a header character dump

Send IRIS DMC a short character dump of the file, since the first few characters in the file can many times reveal the nature of the data. We might be able to tell you what it is and how to access it.

% cat myUnknownFile | od -c | head -50
0000000   0   0   0   0   0   1   V       0   1   0   0   1   1   2   0
0000020   2   .   4   1   5   1   9   9   7   ,   1   5   3   ,   0   0
0000040   :   0   0   :   0   0   .   0   0   2   0   ~   1   9   9   7
0000060   ,   3   0   5   ,   2   3   :   5   9   :   5   9   .   9   9
0000100   7   0   ~   2   0   1   1   ,   0   4   5   ,   1   1   :   4
0000120   7   :   0   0   .   0   0   0   0   ~   I   R   I   S   _   D
0000140   M   C   ~

Tags

data


Updated: 05/18/2017