Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/GCPWORKS">GCPWORKS</a><hr>
<H3>Setup</H3>
To start GCPWorks, type
<P>
<PRE>
    gcpworks
</PRE>
The first panel to appear is the Setup panel.
<P>
<H4>Processing Requirements</H4>
The ``Processing Requirements'' section of the setup panel is used to 
establish the type of processing to be performed.<p>
If ``Full Processing'' is selected then the user is expected to establish
a transformation using both GCPs and a mathematical model as well as perform
a registration of the image.  This option is the most traditional and a good
default.<p>
If ``Collect/review GCPs Only'' is selected, the user will not have the option
of performing a final registration, pre-registration or any mosaicking 
setup.<p>
If ``Mosaic Only'' is selected it is assumed that the input image, and the
output file are already geocoded so that the image warping can be established
on the basis of the georeferencing.  The sequence of steps is streamlined
to performing the mosaicking operation.
<P>
<H4>Mathematical Model</H4>
The Mathematical Model section allows the user to select the type of
mathematical modelling to be used in computing a warping transformation.
The default is Polynomial transform.
<P>
<UL>
<LI> Polynomial: A 1st through 5th order polynomial transform is computed 
based on the ground control points.
</UL>
<UL>
<LI> None: The None mathematical model implies that the transformation should
be based on the georeferencing information, and includes the ability to
transform between projections.  This can only be used if the input image
is already corrected, and no ground control points should be collected.
</UL>
<UL>
<LI> Thin Plate Splines: This mathematical model is also computed based on a
set of GCPs, but is always exact at each of the GCPs.  
</UL>
<UL>
<LI> Satellite Ortho: This mathematical model is based on PCI Satellite Ortho
and DEM extraction package.  
</UL>
<H4>Source of GCPs</H4>
The ``Geocoded Image'' correction process is used to tie down an
uncorrected image to a georeferenced image of the same area. The
final registration step may be performed into another set of
channels, or even another file if desired. ``Geocoded Image'' mode is
the typical process used for mosaicking.<p>
The ``Hardcopy Map on Digitizing Table'' correction process is used to
tie down an
uncorrected image to a georeferenced map mounted on a digitizing
table or tablet.  Corresponding points are selected on the uncorrected image
on screen, and on the digitizing table.<p>
The ``Vectors'' correction process is used to tie down an
uncorrected image to a set of georeferenced vectors of the same
area. Additionally, a backdrop set of imagery may be selected and
displayed in the georeferenced image windows.<p>
The ``User Entered Coordinates'' process is used to assign known
locations to features in the uncorrected image. This is done by
selecting a point on the uncorrected image, and typing in the
georeferenced location of that feature.<p>
The ``Chip Database'' process is used to tie down an uncorrected
image to a set of 1-GCP image chips.  See the Appendix for more
details on the Chip Database.
<P>
<hr>
Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/GCPWORKS">GCPWORKS</a><br>
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