Table of Contents

## NAME

selectfile - selection criteria for seismic data

## DESCRIPTION

Select files permit a user to define exact matching descriptions that will be used by various programs to pick which data records (or other seismic information) will be targetted from a data stream.

Select files have many parts. The basic part of a select file is called a chain. Most select files only have one chain. A single chain contains descriptions of what network/station/location/channel/date-time groupings that are to be considered interesting for selection.

Multiple chains can combined together to make multiple requests in one select file.

Individual chains can be tagged. These tags permit the user to label individual requests. These tags can then be presented back to the user (by software that supports this feature) along with actual data, permitting the user to make very complex requests and build post-processing programs that understand and exploit the nature of the original requests.

## SYNTAX

Selectfiles are comprised of any number of selection specifications that appear one to a line.

### STATION={+ or -}{network code}/{station code}

The station selector adds (+) or removes (-) stations from the list of stations to be considered for selection. Network and station codes may include wildcards. If the +/- codes are omitted, they will default to add (+). Multiple network/station lines can be present to specify a complex set of stations.

This creates two sets of stations (possibily with wildcards): the add-set and the subtract-set. Data selected will be the set specified by the union of the all network/stations in the add-set, with the union of all of the network/stations in the subtract-set subtracted. This resultant set is called the station-set.

### CHANNEL={+ or -}{location code}/{channel code}

This channel selector adds (+) or removes (-) stations from the list of stations to be considered for selection. Location and channel codes may include wildcards. If the +/- codes are omitted, they will default to add (+).

This creates two sets of channels (possibily with wildcards): the add-set and the subtract-set. Data selected will be the set specified by the union of the all location/channels in the add-set, with the union of all of the location/channels in the subtract-set subtracted. This resultant set is called the channel-set.

### DATE={start-date}/{end-date}

This selector adds date ranges into the selection sets. DCC date formats are of the following form: MMMM,JJJ,HH:MM:SS.MMM, where MMMM is the year (with century), JJJ is the Day-of-the-Year (Jan 1 = 1), HH is the hour (0-23), MM is minutes (0-59), SS is seconds (0-59), and MMM is the fractional milliseconds (0-999). The date can be truncated at any punctuation mark after the date.

The union of all of the dates selectors specified result in the date-set. If no dates are selected, the date-set set defaults to all.

### TAG=tag1,tag2,tag3...

The tag selector adds labels to a chain. This information can be returned with the resultant data when it is selected. It is possible that multiple chains will select the same record, in this case, multiple tags might be returned (NOT IMPLEMENTED YET).

### chains

Individual chains are separated by a single forward slash (/) character which appears in the left column by itself. This separator can be omitted if there is only one chain present. The end of file is specified with a double forward slash (//).

## SET THEORY

The records which are determined to be interesting by the selection algorithm for each chain are the set intersection of the station-set, the channel-set, and the date-set. The data returned by the entire request for the select file is the union of all sets returned by each chain.

## EXAMPLES

Select all long period data from all IRIS/USGS stations (except ANMO) for 1994:

> STATION=+IU/*
> STATION=-IU/ANMO
> CHANNEL=+*/L*
> DATE=1994,1/1995,1
> TAG=MAIN
> //

All of the data from ANMO (no TAGs):

> STATION=+IU/ANMO
> CHANNEL=+*/*
> //

A complex multi-chain query involving multiple events and windows.

> STATION=+IU/ANMO
> CHANNEL=+*/LH*
> DATE=1997,200,20:00/1997,201,12:00
> TAG=EVENT1_ANMO_LH
> /
> STATION=+IU/ANMO
> CHANNEL=+*/B*
> DATE=1997,201,05:00/1997,201,06:00
> TAG=EVENT1_ANMO_BH
> /
> STATION=+IU/KIP
> CHANNEL=+*/LH*
> DATE=1997,200,20:00/1997,201,12:00
> TAG=EVENT1_KIP_LH
> /
> STATION=+IU/KIP
> CHANNEL=+*/B*
> DATE=1997,201,05:30/1997,201,06:30
> TAG=EVENT1_KIP_BH
> //

## HISTORY

selectfile evolved from an earlier format on the VAX DCC. It was augmented to add support for network codes and locations when it was brought to the SUN. The TAG facility was developed to support the creation of event SEED volumes.

## SEE ALSO

dumpseed(1)

## AUTHOR

Public Domain Software by Scott Halbert - Allied Signal Technical Services Corporation under contract to the Albuquerque Seismological Laboratory - United States Geological Survey - Department of Interior, United States, North American Continent, Earth/Sol 3, Sagitarius Arm of Milky Way Galaxy.

Table of Contents

- NAME
- DESCRIPTION
- SYNTAX

- STATION={+ or -}{network code}/{station code}
- CHANNEL={+ or -}{location code}/{channel code}
- DATE={start-date}/{end-date}
- TAG=tag1,tag2,tag3...
- chains

- SET THEORY
- EXAMPLES
- HISTORY
- SEE ALSO
- AUTHOR