STAR*NET V6 - Circe

Appendix A STAR*NET Tutorial
Before you exit the Project Options, note another difference in the options from the
previous example. At the bottom of the dialog is an options group specific to grid
jobs. Here you enter the average Geoid Height. This value is always entered in
meters, and it is important to use the correct sign. (It’s negative in the contiguous
United States.) You can also enter average deflections of the vertical due to gravity.
Positive values are in north and east directions. These values can be left at zero, but
if you know there are significant deflections in your project area (i.e. several
seconds), entering these known values here should give you better results.
3. Examine the data file if you wish. As mentioned before, the observation data for this
example is identical to the previous example except that the entered control
coordinates are grid coordinates consistent with NAD83, California zone 0403. The
same data set was used for this example so that, if you wish, you can compare output
results from two identical jobs, one run as local, and the other as grid.
4. Run the network adjustment. Look at the network graphically if you wish – it will
look the same as in the last example. However, if you double click any of the
adjusted points, the displayed coordinates will now, of course, be grid coordinates.
5. View the output Listing file and browse through the various sections as you did in
the last example. Since this job is a “grid” adjustment, you will find some new
information present. Go down to the “Adjusted Station Information” section. First
comes the adjusted grid coordinates. Then directly following are the computed
geodetic positions and ellipsoid heights as shown in the listing window below.
As shown above, next comes a listing of convergence angles and scale factors
computed at every station in the network. The factors include the grid scale factor,
the elevation factor, and the resulting combined factor.
180