Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/STG">STG</a><hr>
<H3>PARAMETERS</H3>
STG is controlled by the following global parameters:
<P>
<pre>Name     Prompt                                  Count     Type
FILI     Database Input File Name                1-64      Char
FILO     Database Output File Name               0-64      Char
DBIC     Database Input Channel List             1         Int
DBOC     Database Output Channel List            1         Int
DBEC     Database Elevation Channel List         0-1       Int
INPXSZ   Input Spacing (range, azimuth)          2         Real
RESAMPLE Resample mode: NEAR/BILIN/CUBIC         4         Char
ESCALE   Elevation Scale and Offset              0-2       Real
DELAY    Time Delay to First Input Pixel         1         Real
OALTI    Altitude Above Sea Level (m)            1         Real
OHEAD    Heading Angle in Degrees                1         Real
OPOINT   Point on Flight Path (E, N)             2         Real
OCOEFF   Coefficients for Line Function          2-9       Real
RANGETYP Range Data Type: SLANT/GROUND           1-6       Char
HEIGHT   Height Above Ground (m)                 0-1       Real
</pre>
<H4>FILI</H4>
Specifies the filename of the PCIDSK image database containing the
input slant or ground range image to be registered.
<P>
<PRE>
 EASI&gt;FILI=&quot;filespec&quot;
</PRE>
<H4>FILO</H4>
Specifies the filename of the output PCIDSK image database to which
the corrected ground range image should be written. This file must
also contain the elevation data channel, if DBEC is specified. FILO
must exist before running STG. If FILO is not specified, FILO
defaults to FILI.
<P>
<PRE>
 EASI&gt;FILO=                    | FILI and FILO are the same 
 EASI&gt;FILO=&quot;filespec&quot;          | FILI and FILO are different
</PRE>
<H4>DBIC</H4>
Specifies the image channel on the input file (FILI) which contains
the input slant or ground range radar imagery.
<P>
<PRE>
 EASI&gt;DBIC=i
</PRE>
If FILO=FILI, then DBIC cannot be the same as DBOC or DBEC.
<P>
<H4>DBOC</H4>
Specifies the image channel on the output file (FILO) to which the
output ground range imagery will be written. DBOC cannot be the same
as DBEC.
<P>
<PRE>
 EASI&gt;DBOC=j
</PRE>
If FILO=FILI, then DBOC cannot be the same as DBIC.
<P>
<H4>DBEC</H4>
Specifies the image channel on the output file (FILO) containing the
elevation data to which to register the input slant or ground range
radar image. If there is no elevation data corresponding to the
output area, then DBEC is not specified and the elevation is assumed
to be zero for the entire output window.
<P>
<PRE>
 EASI&gt;DBEC=k
 EASI&gt;DBEC=                    | no elevation data
                               | elevation assumed to be 0
</PRE>
DBEC cannot be the same as DBOC. If FILO=FILI, then DBEC cannot be
the same as DBIC.
<P>
<H4>INPXSZ</H4>
Specifies the pixel spacing of the input slant or ground range radar
image in metres, for both horizontal (range) and vertical (azimuth)
directions.
<P>
<PRE>
 EASI&gt;INPXSZ=Xsize,Ysize       | two positive real values
</PRE>
<H4>RESAMPLE</H4>
Specifies the type of resampling or image data desired.
<P>
<PRE>
 EASI&gt;RESAMPLE=&quot;NEAR&quot;            | Nearest Neighbour
 EASI&gt;RESAMPLE=&quot;BILIN&quot;           | Bilinear Interpolation
 EASI&gt;RESAMPLE=&quot;CUBIC&quot;           | Cubic Convolution
</PRE>
<H4>ESCALE</H4>
Optionally specifies the scale and offset to apply to the elevation
values in the elevation channel (DBEC) to convert values to metres.
If not specified, scale defaults to 1, and offset defaults to 0.
<P>
<PRE>
 EASI&gt;ESCALE=                   | no scaling
 EASI&gt;ESCALE=scale              | scale (no offset)
 EASI&gt;ESCALE=scale,offset       | scale and offset
</PRE>
The equation for the conversion is:
<P>
<PRE>
 elevation in metres = scale * (value + offset)
</PRE>
For example, to convert elevation values from feet to metres, where
a value of 0 represents 1000 feet:
<P>
<PRE>
 EASI&gt;ESCALE=0.3048,1000        | metres = 0.3048 * (value + 1000)
</PRE>
<H4>DELAY</H4>
Specifies the radar time delay (in microseconds) to the first input
pixel.
<P>
<PRE>
 EASI&gt;DELAY=microseconds         | positive real number
</PRE>
DELAY is used to determine the slant range distance in metres to the
first input pixel in the radar image. This is calculated using the
following formula:
<P>
<PRE>
   slant range distance = DELAY * speed of light / 2
</PRE>
The speed of light is 299.793 metres per microsecond. DELAY * speed
of light is the distance to the ground and back. It is divided by 2
to give the distance one-way.
<P>
<H4>OALTI</H4>
Specifies the aircraft platform altitude (in metres) above sea
level.
<P>
<PRE>
 EASI&gt;OALTI=x                    | positive real value
</PRE>
This parameter is output by FLIGHT and should remain unchanged.
<P>
<H4>OHEAD</H4>
Specifies the aircraft heading (in degrees) clockwise from due
north.
<P>
<PRE>
 EASI&gt;OHEAD=angle                | real value between 0 and 360
</PRE>
This parameter is output by FLIGHT and should remain unchanged
<P>
<H4>OPOINT</H4>
Specifies the UTM coordinates of any point on the flight path.
<P>
<PRE>
 EASI&gt;OPOINT=easting,northing    | positive real values
</PRE>
This parameter is output by FLIGHT and should remain unchanged.
<P>
<H4>OCOEFF</H4>
Specifies the coefficients of the polynomial function which
determines the line number in the input radar image, given the
distance along the flight path in metres from OPOINT. This parameter
must be calculated by the FLIGHT program.<p>
Coefficients a,b,c,d,e,f,g,h,i are assigned in ascending order:
<P>
<PRE>
     L = a + (b * D   ) + (c * D**2) + (d * D**3) + (e * D**4)
           + (f * D**5) + (g * D**6) + (h * D**7) + (i * D**8)
</PRE>
D is the distance in metres from OPOINT, and L is the input radar
image line number. D can be positive or negative, depending on
whether the input line number is ahead of or behind the coordinates
specified by OPOINT.
<P>
<H4>RANGETYP</H4>
Specifies the type of input radar image which is to be corrected.
Two types of radar data are supported: slant range and ground range.
<P>
<PRE>
    EASI&gt;RANGETYP=&quot;SLANT&quot;        | slant range data
    EASI&gt;RANGETYP=&quot;GROUND&quot;       | ground range data
</PRE>
<H4>HEIGHT</H4>
Specifies the assumed aircraft height in metres above the ground,
when the input radar data is ground range (instead of slant range).
HEIGHT must be set to the aircraft height that was assumed when the
input ground range image was created.
<P>
<PRE>
 EASI&gt;HEIGHT=x                   | positive real value
</PRE>
If RANGETYP=&quot;GROUND&quot;, HEIGHT must be specified. If
RANGETYP=&quot;SLANT&quot;, HEIGHT is ignored. The OALTI parameter must
still always be specified.
<P>
<hr>
Parent Topic: <A href="http://www.pcigeomatics.com/cgi-bin/pcihlp/STG">STG</a><br>
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