Location codes are used to logically group channels within a single station deployment. This can be for channels produced by the same sensor, channels produced in a sub-processor, many sensors deployed in a grid or an array, etc.
When used to designate sensors deployed in an array, operators may choose to identify a series of sensors using ordered or otherwise meaningful location code values.
The use and meaning of the location code is generally up to the defining network. However the following guidelines are recommended for consistency across networks:
Channels that are closely related should have the same location code, e.g. channels from the same instrument that differ only in orientation or sampling rate, like
S_H_Z, should have the same location code.
Sharing a single location code does not necessarily imply the channels come from the same instrument, e.g. the primary seismometer and primary accelerometer might both have location code
00even if they are physically separate instruments.
The primary seismic channels at traditional seismic stations should have location code of
00or be empty.
Use of an empty location code is recommended only for stations that do not have multiple instruments of the same type and have traditionally not used location codes.
Sensors in an array within a station may be logically grouped in a regular, systematic scheme, e.g. incrementing numbers for a linear array, or using two identifiers separated by a dash for a 2D grid.
Alpha-numeric ordering should be considered desirable, e.g. using
10for a linear array.
Otherwise the network may use the location code for any meaningful system of organizing and namespacing channels at a station.