STAR*NET V6 - Circe

Chapter 5 Preparing Input Data
LEVELING DATA TYPE
The leveling data type lets you integrate differentially leveled observation information
into a 3D adjustment. These observations are similar to “elevation difference”
observations which may be entered with the “V” line, except that weighting is based on
either a given distance or number of turns between the stations.
The “LW” Code: Differential Level Weighting
LW Standard Error per Unit Length [“TURNS”]
Default weighting (standard error per unit length) is defined using the “LW” line. This
line may appear anywhere in the data before the first “L” observation line. You can
change the weighting anywhere in the data by entering another “LW” line. Weighting for
differential leveling observations is not affected by centering errors defined for
traditional observations set in the Project Options.
If the keyword “TURNS” in entered following the standard error value, the Distance
value entered on the “L” line described below will be taken as the number of turns
between the two stations rather than the distance.
The “L” Codes: Differential Level Observation Information
L From-To ElevDiff Distance [Standard Error]
The distance value entry on the “L” line along with the default standard error per unit
length value specified on the “LW” line is used to compute the actual standard error for
the observation used in the adjustment. If an optional standard error value is entered on
the “L” line, this value is used as the actual standard error.
The optional standard error may also may be one of the special “!” or “*” characters to
indicate the observation is to be completely fixed or free.
The Standard Error per Unit Length Value is based on current project units:
If units are Meters, the standard error per unit length is in Meters/KM.
If units are Feet (US or International), the std error per unit length is in Feet/Mile.
If units are anything else, the standard error per unit length is in Units/Unit.
If the Length item is in Turns, the standard error per unit length is in Units/Turn.
Units of the weighting specifications and leveling data are the same as the units set in the
Project Options or as by reset in the data file by the last use of a “.UNITS” inline option.
For complete details of using the “.UNITS” inline, see “Using Inline Options” later in
this chapter.
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