How to put station location information into SH/SHM

To be able to apply array operations like beamforming or vespagrams or for computing source locations SH/SHM needs station information of the records. This information is read from a file $SH_INPUTS/STATINF.DAT only. Station information specified in data input files like GSE is ignored. The format specifications of the STATINF.DAT file are:

• one line per station
• the line must begin with the station name to define in uppercase letters
• the station information follows in any order in the format <keyword>:<value>

Valid keywords are:

lat

station latitude in degrees (required)

lon

station longitude in degrees (required)

elev

station elevation in m (optional)

array

unique number to distinguish different arrays, in particular which relative locations refer to each other (optional)

xrel

relative location in EW-direction in km (optional)

yrel

relative location in SN-direction in km (optional)

name

describing text, replace blanks by underscores (optional)

After the STATINF.DAT file has been modified, it is recommended to restart SH/SHM, since it holds an internal cache for the station entries.

The way SH/SHM computes relative locations xrel and yrel from latitude and longitude is:

lat := location latitude; 
lon := location longitude
reflat := latitude of reference point; 
reflon = lon. of reference point
C := 111.19 km/deg
x = (lon - reflon) * C * cos(lat)
y = (lat - reflat) * C

The code fails definitely if an array is located across the zero meridian.

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