STAR*NET V6 - Circe

Chapter 10 Adjustments in Grid Coordinate Systems
10.6 Selecting a State Plane Zone
State Plane Coordinate System (SPCS) includes the NAD83 and NAD27 grid systems
used in the United States.
To select a zone, choose NAD83 or NAD27 from the Grid selection dropdown selection
list shown in the previous section, and the zone selection dialog will automatically
appear. Or if NAD83 or NAD27 is already selected, simply press the large zone list
button to select a new zone.
To select a particular zone, either type the zone number (including any leading zeros) in
the “Zone” field, or use your mouse to scroll through the selection list and click on a
zone to highlight it. Press the “Show Parameters” button if you wish to see the zone’s
projection type and its parameters.
Press OK to actually choose the zone and exit the dialog. Or simply double-click the
zone from the selection list to choose it and exit the dialog in a single step.
Zone parameters for both NAD83 and NAD27 state plane systems are stored in a text file
named STAR6.SPC located in the same directory you installed STAR*NET. Since this
file is a standard text file, you can view its contents using any text editor. It contains four
sections, two sections for Lambert and Transverse Mercator for NAD27, and likewise
the same two sections for NAD83.
By definition, the NAD83 system is based on the GRS-80 ellipsoid and the NAD27
system, on the Clarke 1866. These ellipse parameters are built into the program.
The STAR6.SPC state plane coordinates parameters file is not meant to be edited and
therefore no documentation on its format or contents is provided. Users wishing to create
custom grid zones, for either domestic or international zones, should enter their
parameters in the STAR6.CUS file described later in this chapter.
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