https://github.com/savage13/sacio
sacio library
https://github.com/savage13/sacio
c iris sac sacio-library seismic
Last synced: 6 months ago
JSON representation
sacio library
- Host: GitHub
- URL: https://github.com/savage13/sacio
- Owner: savage13
- License: bsd-2-clause
- Created: 2019-07-27T13:06:19.000Z (about 6 years ago)
- Default Branch: master
- Last Pushed: 2024-05-30T15:54:47.000Z (over 1 year ago)
- Last Synced: 2025-04-11T11:54:27.026Z (6 months ago)
- Topics: c, iris, sac, sacio-library, seismic
- Language: C
- Homepage: https://savage13.github.io/sacio/
- Size: 822 KB
- Stars: 8
- Watchers: 2
- Forks: 3
- Open Issues: 1
-
Metadata Files:
- Readme: README.md
- License: License
Awesome Lists containing this project
README
libsacio Documentation
======================
[](https://travis-ci.com/savage13/sacio)
Overview
--------
The sacio library, libsacio, provides an interface to read and write sac files and manipulate their contents.
SAC Files
---------
SAC (Seismic Analysis Code) files are binary or alphanumeric data files for storing time series data, primarily ground motion recorded by seismometers. Format of the SAC file consists of a metadata header followed by the ground motion stored as equally or unequally spaced in time. The data section may also be the Fourier Transform of an input ground motion or a 2D data set.
Documentation
-------------
[libsacio Documention](https://savage13.github.io/sacio/)
IRIS-SAC Relationship
---------------------
The code and library here was originally written and licensed under the [2-Clause BSD License](https://choosealicense.com/licenses/bsd-2-clause/) and subsequently included for the [IRIS-SAC distribution](http://ds.iris.edu/ds/nodes/dmc/forms/sac/). 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](http://ds.iris.edu/ds/nodes/dmc/forms/sac/)
Examples
--------
Examples of using the library can be found within the [documenation](https://savage13.github.io/sacio/). Of particular note are:
- [sac_read()](https://savage13.github.io/sacio/html/group__sac.html#gab2623928ccd5cac1a4cc94be5dd89273)
- [sac_write()](https://savage13.github.io/sacio/html/group__sac.html#gafe8cd1cadc546ea9d67a5ca14fd3886d)
- [sac_get_string()](https://savage13.github.io/sacio/html/group__sac.html#ga58de657b18177e79b5fa001b21c55e32) / [sac_set_string()](https://savage13.github.io/sacio/html/group__sac.html#ga9acd9d129945c8fdf5a21434ce1d3359)
- [sac_get_int()](https://savage13.github.io/sacio/html/group__sac.html#ga65ddb9d01a8d1ea66bc7ad1024b30534) / [sac_set_int()](https://savage13.github.io/sacio/html/group__sac.html#ga65ddb9d01a8d1ea66bc7ad1024b30534)
- [sac_get_float()](https://savage13.github.io/sacio/html/group__sac.html#ga94ddfd21929cd9cb6faa508d8b6d1460) / [sac_set_float()](https://savage13.github.io/sacio/html/group__sac.html#gaa5cd583512409156b09d6a4b0ec4b683)
Documentation for each function includes a selection of example usage (these also function as tests).
Within the test directory `t` are a set of example programs that use the library. The best programs to get started are:
- [t/iotest.c](t/iotest.c) - Reading of all data files and accessing header and data values
- [t/cut.c](t/cut.c) - Reading data files with a imposed time window (cut)
- [t/cutim.c](cutim.c) - Windowing data within memory (cut)
- [t/compat.c](t/compat.c) - Usage of the library with original sacio library function names
- [t/ver.c](t/ver.c) - Examples of behavior differences between v6 and v7 SAC header files
### Read, Change and Write a sac file
Compile and run the example below using (assuming you have compiled the library):
gcc -I. -o example example.c libsacio_bsd.a
./example t/imp.sac
The file `t/imp.sac` is an impulse function and distributed with `sacio`.
If you have not compiled the library yet, see the [Compiling](#compiling) section below.
The library does not need to be installed to compile/run the example code, it only needs
to know where the header file `sacio.h` is.
If you have compiled and installed the library, the example below can be compiled using:
gcc -I/usr/local/include/sacio -o example example.c -L/usr/local/lib -lsacio_bsd
./example t/imp.sac
```c
#include
#include
int
main(int argc, char *argv[]) {
// Variable Declaration
int i;
int nerr = 0;
char org[128] = {0};
char id[64] = {0};
double delta;
sac *s = NULL;
if(argc < 2) {
printf("Usage: example file.sac\n");
return -1;
}
// Read a SAc file, could be evenly or unevenly spaced
s = sac_read(argv[1], &nerr);
if(nerr != 0) {
printf("Error: %d reading file\n", nerr);
return -1;
}
// Get a floating point value: delta
sac_get_float(s, SAC_DELTA, &delta);
// Print out some header values
printf("delta: %f\n", 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(org), "%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);
return 0;
}
```
Downloading and installing
--------------------------
### Downloading
This library can be downloaded directly by either going to **Code->Download Zip** or by using git as:
git clone https://github.com/savage13/sacio.git
This library is self contained and does not require any additional dependencies.
### Compiling
Once downloaded, the library can be compiled from within the `sacio` or `sacio-master` directory using:
./configure
make
### Installation
Installation to the default location `/usr/local` can be completed using:
make install
This will install `libsacio_bsd.a` into `/usr/local/lib/libsacio_bsd.a` and
`sacio.h` and `timespec.h` into the `/usr/local/inclucde/sacio` directory. Creating
a symbolic link to this library will assist in existing programs that require
the sacio library, e.g.:
ln -s /usr/local/lib/libsacio_bsd.a /usr/local/lib/libsacio.a
Passing the `--prefix` option to the configure command allows a different installation location.
### Testing
Tests for the library can be run if desired using
make test
Community Guidelines
--------------------
### Issues / Bugs
Please report issues, possible bugs, inconsistencies, and improvements to the project in the Issue Tracker or using a Pull Request.
### Contributions
If you would like to contribute to the project please file Pull Requests and/or create issues for discussion at the libsacio project.
### Support
The best place to find support for this library and the IRIS version of SAC (and where you can find me),
is on the [sac-help mailing list](http://ds.iris.edu/message-center/topic/sac-help/).
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.