MASTER STATION LOCATION/HISTORY FILE (calsta2000.loc)
The file calsta2000.loc (also know at the NCEDC as ncsn.stations)
presently resides in Menlo Park on andreas.wr.usgs.gov in
/home1/calnet/klein/stas/ and also in ftp anonymous in
ehzftp.wr.usgs.gov/klein/stations. Additional stations not currently
used in NCSN phase data are in more2000.loc in the same directories.
The file calsta2000.loc has the complete history of the NCSN network.
The file has most stations in the surrounding networks but is not
updated as frequently. The on and off dates are as accurate as
possible. Calsta2000.loc also has the station name history. Codes
are here for pre-1977 (4-letters), 1977-1986 (4-letters including
component), 1986-1994 (5-letters including net and component), and
1994-2006 (10-letters including net and component). The "unique" or
"universal" station codes consist of a 3-5 letter site code, 2-letter
net code and 3-letter USGS component codes. The 1-letter component
code is used as a label in various station files, but is not unique.
Starting in 2006, it is expected that 3-letter SEED component
codes will be used instead of the USGS codes. The ambiguity of SEED
codes, together with station moves, also requires 2-letter location
codes. The SEED station codes consist of a 3-5 letter site code,
2-letter net code, 3-letter SEED component codes, and a 2-letter
location code. The location code "-" is used as a default for station
where a location code tie-breaker is not required.
Most NCSN stations with coordinates to 4 decimal places of minutes of
lat/lon have been surveyed with GPS instrumentation. These precise
locations have mostly replaced the locations estimated from a
topographic map, that are all that is available for abandoned sites.
The elevation at these GPS sites is referenced to the geoid instead of
sea level.
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Table 1. FORMAT OF STATION LOCATION FILE
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cols. length heading data
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1-5 5 SITE Station site code (within its own network)
6-7 2 NET Unique station net code (assigned by IRIS)
9-11 3 USGS USGS component (channel) code (SEED for some digitals)
These 3 fields are the "unique" station code (1994-2006).
13-15 3 RATN Station name code (Rationalized code 1986-94)
16 1 1-letter network code (Rationalized code 1986-94)
18 1 C 1-letter component code (Rationalized code 1986-94)
21-24 4 4LET "New" 4-letter code 1977-86, 4th letter is the component
26-29 4 OLD "Old" or standard code (pre-1977 for USGS)
31-32 2 LAT North latitude, degrees
34-40 7 North latitude, minutes (F7.4)
42-44 3 LON West longitude, degrees
46-52 7 West longitude, minutes (F7.4)
55-58 4 ELEV Elevation, meters
60 1 R Geographic region code of Eaton
61 1 G GPS/topo datum & location status code (see below)
63-84 22 Full geographic name. "&" in col 84 if the channel is a
duplicate and temporary alias name no longer used (DDI aka
HV1) or an additional decimation with the same SNC code.
85 1 Colon (:) if non-USGS station recorded in Menlo Park,
Semi-colon (;) if non-USGS station formerly recorded in MP
Comma (,) if non-USGS station maintained but not recorded,
or used in another station database.
86-89 4 ORG Network owner/operator code
90-97 8 OPERATN Start date of operation of instrument (YYYYMMDD)
99-106 8 End date of operation of instrument (YYYYMMDD)
109-116 8 DATAUSE Start date of USGS-MP usage of data (YYYYMMDD)
118-125 8 End date of USGS-MP usage of data (YYYYMMDD)
127-129 3 SEED SEED code for component, non-unique mapping to USGS code.
131-132 2 LOC 2-letter location code for breaking ties, not used yet.
134-137 4 ON On time (hr-min GMT) of start date of operation.
139-142 4 OFF Off time (hr-min GMT) of end date of operation.
144-147 4 JPE Jerry Eaton's station name. Same as 4-letter name for
USGS-Menlo stations.
149-152 4 ALIAS Alias, erroneous or unofficial name.
154-157 4 Additional alias, erroneous or unofficial name.
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Table 2. GPS/topo datum & location status code table
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(see spreadsheet.txt for more notes about the use of this location
status code in the NCSN)
code definition: comment:
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A WGS84 handheld GPS of sensor Most common NCSN case, within 2 meters
of sensor.
B WGS84 sensor offset from GPS Offset (distance & azimuth) estimated
from nearby GPS location.
E WGS84 GPS external antenna Self-reported GPS of telemetry antenna.
N WGS84 nearby handheld GPS GPS of nearby, outdoor location.
D WGS84 hi-acc differential GPS The highest accuracy GPS we can do
(seldom used).
C WGS84 from topo map location Never GPS'ed, converted from topo map.
T NAD27 topo map Never GPS'ed, from topo map only,
ie from abandoned site.
W WGS84 either antenna/sensor GPS exact site undocumented.
blank Not yet determined.