STAR*NET V6 - Circe

Example of Leveling Data
Chapter 5 Preparing Input Data
Leveling data can be added to other data in a 3D adjustment. This data can be entered to
supply vertical observations to all stations in a network, to some of the stations in a
network, or to add vertical redundancy to stations already being defined by other kinds of
observations such as zenith angles or elevation differences.
Any station named in leveling data, however, must also have other data present which
will define its horizontal location. Therefore, a station in a 3D adjustment named only in
an “L” line will cause an error and the adjustment will terminate.
The example data below illustrates leveling information that may be integrated with
some other data in a 3D adjustment.
# Leveling Data
LW 0.08
L 33-79 2.546 1798
L 79-80 -4.443 931
L 79-81 0.231 855 'Bench 81-1987
L 80-132 1.322 2509 0.14
L 92-93 -5.024 752
LW 0.05 # Changing the default weighting
L 12-15 0.244 1245
LW 0.15 TURNS # Changing to weighting based on turns
L 12-19 3.145 3
etc...
Assuming that units for this project is meters, the first “LW” line indicates that the
standard error per unit length is set to 0.08 Meters/Km. The actual standard error used
for any elevation difference observation in an “L” line is then propagated from this 0.08
value and the distance between stations.
On the “L” line describing observations between stations “80” and “132” an explicit
standard error value of 0.14 meters is given. This actual standard error value will be used
for the observation rather than a propagated value.
The last “LW” line illustrates entering a standard error per turn. The actual standard
error used for subsequent “L” lines will be propagated based on the 0.15 meters/turn
value and the number of turns entered.
Note that when viewing a plot diagram of a network containing leveling observations,
straight lines are drawn between stations containing these observations even though in
reality, these lines are likely made up of many turning points which may wander as the
survey did, perhaps around a hill for example.
75