STAR*NET V6 - Circe

Chapter 4 Options
Option Group: Distance/Vertical Data Type
This option changes how STAR*NET interprets input distance and vertical information
in 3D data. If set to “Slope Dist/Zenith”, distance observations are interpreted as slope
values and vertical observations as zeniths. If set to “Horiz Dist/Elev Diff,” they are
interpreted as horizontal distances and elevation differences.
An inline “.DELTA” option may be used anywhere in data files to change the default
type of Distance/Vertical data being entered.
Option Group: Earth Radius/Refraction Information
Earth Radius of Curvature for Local Jobs – When running local jobs, this value is
used in many curved-earth geometry calculations including the reduction of slope
distances to horizontal, and the reduction of observations to specified datums.
The generally accepted average value of 6,372,000 meters is set as the default when
the program is installed, however you can change it to another value if it is known to
be different for your geographical area. Note that this radius is used only for local
jobs. Earth radius values for grid jobs are automatically calculated based on station
position and azimuth using published geodetic formulas.
Default Coefficient of Refraction – The value of 0.07 is set as the default when the
program is installed, however you may reset it to any value you feel is proper for the
atmospheric conditions known for your job. The value of the coefficient only affects
internal corrections applied to zenith angles during the adjustment. The zenith angles
shown in the output listing do not reflect these corrections for refraction.
Note that a “Reset” button is present for both items in this group. Press it to reset a
value back to the default setting value present in the “Company” options.
An inline “.REFRACTION” option may be used anywhere in data files to change the
default refraction value for different sections of your data.
Note that STAR*NET uses the “classical text book” index value of 0.07 as the
generally accepted average value for most field conditions This average refraction
index value and the method used to apply the correction is detailed in the publication
“Geodesy” by G. Bomford. See Appendix section C.2 for additional information.
STAR*NET assumes that all entered data are normal measurements taken on the
face of the earth. If you have removed the effects of earth curvature and refraction by
hand-modifying your zenith angles by some method, you must indicate this in your
data by using the “.CURVE OFF” inline option so that STAR*NET will not perform
curvature corrections on already corrected data. See Chapter 5, “Preparing Data,” for
a description of the “.CURVE OFF” inline option.
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