libsacio Documentation

Overview

The sacio library, libsacio, provides an interface to read and write sac files and manipulate their contents.

Documentation

libsacio Documention

IRIS-SAC Relationship

The code and library here was originally written and licensed under the 2-Clause BSD License and subsequently included for the IRIS-SAC distribution. This distribution also includes other, essentially, public domain knowledge on the sac format. The code found here is the same included within the IRIS-SAC distribution, but does not included the licensed code from LLNL/IRIS; this is primarily the processing, filtering, and data operations. If you require the SAC program and this functionality, make that request to IRIS

Examples

Read, Change and Write a sac file

#include <stdio.h>

#include <sacio.h>

// Variable Declaration
int nerr = 0;
char org[128] = {0};
char id[64] = {0};
sac *s = NULL;

// Read a SAc file, could be evenly or unevenly spaced
s = sac_read("file.sac", &nerr);
if(nerr != 0) {
    printf("Error: %d reading file\n", nerr);
    return;
}

// Print out some header values
printf("delta: %f\n", s->h->delta);
printf("npts:  %d\n", s->h->npts);
printf("comps: %d\n", sac_comps(s));

// Print out the first 5 data values
for(i = 0; i < 5; i++) {
    printf("y[%4d]  %f\n", i, s->y[i]);
}

// Set some header character string values
sac_set_string(s, SAC_NET, "IU");
sac_set_string(s, SAC_STA, "BORG");
sac_set_string(s, SAC_LOC, "00");
sac_set_string(s, SAC_CHA, "BHZ");

// Set the origin time to 1994/160 00:33:16.123
sac_set_time(s, timespec64_from_yjhmsf(1994, 160, 0, 33, 16, 123));

// Format the origin time in absolute time
sac_fmt(org, sizeof(ostr), "%TO", s);
printf("Origin Time: %s [Absolute]\n", org);

// Output the Station id: NET.STA.LOC.CHA
sac_fmt(id, sizeof(id), "%Z", s);
printf("Station ID: %s\n", id);

// Write out the modified sac file
sac_write(s, "output.sac", &nerr);

Downloading and installing

Please report issues to the project.

If you would like to contribute to the project please file Pull Requests and/or create issues for discussion at the libsacio project.

Included Libraries

• 64-bit time https://github.com/evalEmpire/y2038 (MIT License)
• GeographicLib https://geographiclib.sourceforge.io/ version 1.49 (MIT/X11 License)

License

The code here is licensed under the 2-Clause BSD License, except where specified.