Geodolite Trilateration Data Set

For a description of the data collection procedures and precision, see: Savage, J.C., and W.H. Prescott, Precision of Geodolite distance measurements for determining fault movements, Journal of Geophysical Research, 78, 6001-6008, 1973.

Geodolite Positions

Geodolite Line Lengths

Position Column Descriptions

Columns Contents
1-5 Network name
7-14 Station name
18 Source of coordinates (see codes at end of file)
20-21 Latitude degrees (north positive)
26-31 Latitude minutes
23-24 Latitude seconds
34-37 Longitude degrees (east positive)
39-40 Longitude minutes
42-47 Longitude seconds
53 Source of elevation (see codes at end of file)
55-61 Elevation (m)
65-66 Type of center mark (see codes at end of file)
68-80 Information stamped on monument

Line Lengths Column Descriptions

Columns Contents
1-5 Network name
7-14 Station 1 name
16-23 Station 2 name
25-26 Year (2-digit, always in 1900s)
27-28 Month
29-30 Day of month
32-35 Time (hhmm)
37-41 Azimuth (clockwise from north, decimal degrees)
43-53 Mark-to-mark distance (m)
55 Reduction code (+=latitude properly accounted for in pressure reduction, /=latitude was ignored)
56-66 Distance on Clarke spheriod (m)
68-74 Standard deviation (m)
76-80 Code ([blank]=geodolite, red=reduced [from an eccentric], g8=geodimeter)
Note: the casual user can ignore the remaining columns
83-91 Mean ranging (m)
93-97 Mean offset (m)
99-105 Mean index of refraction
107-112 Mean air temperature (degrees K)
114-120 Mean air pressure (mb)
122-126 Mean vapor pressure (mb)
128 Original reduction code ([blank] or $)
130-136 Correction to convert [blank] or $ to / (m)
138-144 Elevation of Station 1 (m)
146-150 Instrument constant (m)
152-156 Instrument Height 1 (m)
158-156 Instrument digiquartz #1 id
163-166 Instrument digiquartz #2 id
169-172 Instrument operator
163-166 Instrument id
182-188 Elevation of Station 2 (m)
190-194 Reflector constant (m)
196-200 Reflector Height 1 (m)
202-205 Reflector digiquartz #1 id
207-210 Reflector digiquartz #2 id
213-216 Reflector operator
218-223 Reflector id
224 Processing direction (1=Sta 1 to Sta 2, 2=Sta2 to Sta1)
226-229 Aircraft recorder id
231-233 Probe 1 id
235-237 Probe 2 id
239-241 Airspeed (knots)
242-243 Number of aircraft passes
245-255 Old arc distance using Bomford refractivity