Spectra Precision FAST Survey Reference Manual - Manual (Page 104)

p102
 Projection
: If you click the arrow to the right of the current projection, you can select from a list of projections that
you have previously created. But to select a projection that you haven’t previously used, choose Edit Projection
List
.
 Convert WGS84 to NAD83
. Most base stations in North America broadcast NAD83 positions. Turn this option
on when a North American base station is transmitting WGS84 positions. Leave this option off for all other
situations.
 Edit Projection List
: Click this button to select a predefined projection or define a new projection.
 Add Predefined:
If you click Add Predefined, you can set the country/projection to use at the top of the dialog,
then choose the zone within the projection. For example, in the United States, State Plane 83 is a common
projection, with various grids available covering all states. If Austria is selected, options for that country appear.
 Country:
Some of the projections available for selection in the Country category are discussed below:
NAD 27:
When selecting this coordinate system, you will also need to specify a state plane zone. FAST
Survey will use data files to perform a NADCON datum shift from WGS84 to NAD27 coordinates. By
default, only data files for the continental U.S. are loaded to the data collector. If you are working outside this
region, please load the appropriate files from your CD to the SurvStar\NADConv directory. NAD27 uses the
Clarke 1866 ellipsoid.
NAD 83:
When selecting this coordinate system, you will also need to specify a state plane zone. NAD 83
uses the GRS80 ellipsoid.
UTM:
The ellipsoid used in the Universal Transverse Mercator calculation is determined by the Datum
selection. If you choose the option, “WGS 84/Automatic Zone Selection”, the zone is determined by the
lat/lon values read in from the receiver. If you know your UTM zone, you can also select it. Whenever FAST
Survey does a reverse calculation (from UTM to WGS84) you will be prompted to enter a zone number.
3TM (Canada):
This system is also referred to as “MTM”. It is a 3 degree zone width Transverse Mercator