Spectra Precision FAST Survey Reference Manual - Manual (Page 278)

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Then you proceed from the current location to the target station. In fact, although the points that are stored may contain
station and offset descriptions, the data stored to the raw file pays no attention to the centerline information. The station
and offset on the screen act only as a check on your current location. The direction of taking the sections, (L to R or R
to L), is important and is set by specifying “Chainage Direction”. Unlike with the SCT format method, pressing Menu
to exit does not store the data, but instead the data is automatically stored as you go, as a series of 37 (N), 38 (E) and 39
(Z) record types (Geodimeter format), with header line records, as shown below:
50=XSEC1
54=104 North
0=As-Builts 240-300
53=VF
90=2
97=0
51=3-28-2004
56=65.0
74=30.10
55=3
96=2
6=2.100
80=280.000
91=1
37=5105.857
38=5069.091
39=991.905
37=5104.091
38=5074.931
39=990.724
Starting left to right, the data points begin with a 91=1 record. A right to left section would begin with 91=2. When you
“cross 0” or are on the centerline or baseline, you click the CL/BL button which sets a 92=1 record for centerline and
92=2 for baseline, and the next shot is the centerline/baseline shot. If you select the “-0.00” button, this indicates
whether the next shot is a tie-in (catch) or extension beyond the tie-in. This sets a 93=1 record for the catch and 93=2
for the extension prior to the subsequent coordinate record. In effect, you tell the program where the centerline or
baseline is by shooting that point. Then the station and offsets of the shots for that cross section are determined relative
to that center-of-alignment shot. It does not use a horizontal alignment combined with rounding to determine the station
and offset of the shots (like the SCT method does). You tell it the station, the direction of measurement (left to right or
vice versa) and you tell it which one is the center shot. This is why the Raw/Geodimeter method is the only method that
works with no centerline (the “None” option). For each section, you tell it the station and center shot, and all other
measurements are used to determine the left and right offsets relative to the center shot. If the L to R method was used,
shots before the center shot are on the left, for example, and their offset is determined by the inversed distance to the
center shot. The centerline file or other form of horizontal alignment, if selected, is academic and only used to advise
you on your current station and offset. The CHK button will allow checking into known points to be sure that tight
coordinate control is maintained. N moves onto the next station as defined by the interval set using the Sta button.
Note:
The .SCT file method is the standard Store Sections method. The RAW/Geodimeter method is a flexible