STAR*NET V6 - Circe

Chapter 5 Preparing Input Data
The “BM” Code: Bearing and Measurements to Another Station
Format for 2D Data:
BM From-To Bearing (or Azimuth) Distance [Std Errs]
Formats 3D Data - Depending on the “Distance/Vertical Data Type” mode:
BM From-To Bearing (or Az) Slope Dist Zenith [Std Errs] [HI/HT]
BM From-To Bearing (or Az) Horiz Dist Elev Diff [Std Errs] [HI/HT]
The “BM” data line is identical to the standard “M” data line except that it contains a
bearing or azimuth value rather than an angle. The station string contains only the
“From-To” stations rather than the “At-From-To” stations required for an angle.
This data line type is particularly useful for setting a point when a bearing or azimuth
(rather than a turned angle) is known to the target station.
Just as with the “M” data line, the distance and vertical information in 3D data may be
either a Slope Distance and Zenith Angle, or a Horizontal Distance and an Elevation
Difference, depending on the setting of the “Distance/Vertical Data Type” option in the
Project Options. And the mode can also be changed anywhere in your data file by using
the “.DELTA ON/OFF” inline option.
The examples shown below illustrate 2D and 3D data lines, one with a bearing and the
other with an azimuth.
Example 1: (2D Data)
BM 5-88 N32-44-52.5 1245.425 ! ! ‘Mark 887
The bearing and distance from “5” to “88” are both given, and both will be fixed in the
adjustment because of the “!” fixity symbols assigned to each.
Example 3: (3D Data with Azimuth, Slope Distance and Zenith Angle)
BM 44-42 23-33-46.7 1102.42 89-13-12 2 & &
The azimuth from “44” to “42” is 23-33-46.7 and it is given a standard error of 2.0
seconds. The distance and zenith angle entries will be assigned the default standard
errors as defined in the project options.
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