Input file name. This parameter is input as
INP=in
where
in is the input file name.
In addition, a second file may be specified which contains the
line and sample (tiepoint) parameters. If this second file is specified,
the parameter would then be
INP=(in,pds)
where
PDS is the name of a program-MAP-type parameter data set.
Note : The second input file (pds) is used only in conjunction with
program MAP.
LGEOM is almost always run with the PARMS parameter
as the means of entering the TIEPOINT, NAH, and NAV parameters.
The size field is specified with four arguments,
SIZE=(a,b,c,d)
where:
a is the starting line number of the output picture.
b is the starting sample of the output picture.
c is the number of lines, and
d is the number of samples
For example, SIZE=(1,1,40,50)
would create an output picture of size 40 lines by 50 samples.
Usually defaulted (SL=1). SL tells the program where in the output coordinate system to start the output image. The output coordinate system is the system used for all (newline,newsample) coordinates in the TIEPOINT parameter.
Usually defaulted (SS=1). SS tells the program where in the output coordinate system to start the output image. The output coordinate system is the system used for all (newline,newsample) coordinates in the TIEPOINT parameter.
NL can be used in conjunction with NS in place of the SIZE parameter to specify the size of the output picture. It simply represents the number of lines for output.
NS can be used in conjunction with NS in place of the SIZE parameter to specify the size of the output picture. It simply represents the number of samples per line for output.
IDSNAM is an optional parameter which can be used to specify the name of the intermediate data set. This is often used to change the location of the data set. This data set is usually slightly larger than the output file, but may be up to 2 times as large in some cases. For example, if the user's current directory is USERDISK:[USER], and he/she does not have enough disk space for IDS, then he/she could input IDSNAM=SCX:[USER]LGIDS or some such name to ensure that the IDS ends up in a valid directory with enough disk space to hold it. On VMS systems the user may define a DCL logical name of LGIDS to avoid having to specify the parameter repeatedly. For example, if before running the LGEOM job the user inputs DCL DEFINE LGIDS SCX:[USER]LGIDS then all subsequent lgeom jobs would point to that Intermediate data set until the logical name was deassigned (DCL DEASS LGIDS).
IDSNS is an optional parameter which may be used to change the number of bytes per line in the Intermediate Data Set. The main purpose of this parameter is to allow the user to "tune" LGEOM to obtain the optimum speed. (The value should gradually decrease from its default value of 1000 when NL or NS get large and the working set is small.) The program may change the value of IDSNS if it is necessary for avoiding aborting execution due to insufficient memory.
Physical memory (megabytes) available for LGEOM dynamically allocated buffers. This applies to non-VMS systems only. The default is 16.0. (The maximum value is 2047 (megabytes), to insure that the number of bytes can be stored as a 32-bit integer.) This parameter can usually be defaulted. If the amount of memory available is less than the default, then PMEM should be set accordingly to prevent the program from thrashing. If the amount of memory available is more than the default, then PMEM may be set accordingly to allow larger images to be handled in one pass.
RATIO is used to estimate the number of blocks in the Intermediate Data Set and allocate a memory buffer to map the blocks. The default value of 2.0 should cover all but very unusual cases. RATIO is the factor by which the Intermediate Data Set exceeds the Output Data Set.
WSA is an optional parameter to reduce the working set size that LGEOM automatically determines. The default value is 150,000 bytes to allow for I/O buffers etc.
NOIN means no interpolation. The default method for computing the
DN values of the output picture is to use a bi-linear interpolation
on the four nearest neighbors in the input picture. With NOIN, the
value of the nearest point is simply used.
For example, say a point in the output picture was determined
to have come from point (R,P) in the input picture. Since R and P
are real values, we must somehow calculate a DN value for that
point. Take IR and IP as the truncated values. We then have
VAL1 VAL2
* *
(IR,IP) (IR,IP+1)
POINT
*
(R,P)
VAL3 VAL4
* *
(IR+1,IP) (IR+1,IP+1)
Here, POINT is the result of a bilinear interpolation using
VAL1, VAL2, VAL3, and VAL4.
If NOIN is specified, then POINT would be VAL1, the nearest
neighbor.
NOIZ means no interpolation with zero DN values. Whenever an interpolation is to be done and one of the points is zero, nearest neighbor is used. This option is used when zero represents missing data and you do not want to interpolate between good data and missing data.
Causes a listing of the TIEPOINT parameters to be generated and causes periodic progress messages to be printed (Default is that no such listing is printed.)
The format is obtained from the input image label.
NAH=N where N is an integer value specifing the number of areas horizontally; which is also the number of columns of tiepoints less 1. NAH must be specified unless an optional dataset containing the parameters NAH, NAV and TIEPOINTs is specified. (2nd optional input dataset if the dataset is created by program MAP, optional parameter dataset (see PARMS parameter) if the dataset is created by any other program besides program MAP). NAH must also be >= 1.
NAV=N where N is an integer value specifing the number of areas vertically; which is also the number of rows of tiepoints less 1. NAV must be specified unless an optional dataset containing the parameters NAH, NAV, and TIEPOINTs is specified (2nd optional input dataset if the dataset is created by program MAP, optional parameter dataset (see PARMS parameter) if the dataset is created by any other program besides program MAP). NAV must also be >= 1.
TIEPOINT=(newline(1),newsamp(1),oldline(1),oldsamp(1),newline(2),...). The values of TIEPOINT specify the mapping of control points between output and input pictures. The numbers which follow the keyword are in multiples of four, one multiple of four for each tiepoint. The numbers may be either integer or real type. However since the grid in the output must be rectangular, the (newline,newsamp) points must be whole numbers. The total number of tiepoint numbers must be 4*(NAH+1)*(NAV+1) Within each group of four numbers describing a tiepoint, the first number specifies the line coordinate of that tiepoint in the output (transformed) picture, the second number specifies the sample coordinate of that tiepoint in the output picture, the third number specifies the line coordinate of the input picture and the fourth specifies the sample coordinate of the input picture. The order in which the tiepoints are specified is left to right within a horizontal row of tiepoints. The horizontal rows of tiepoints are specified in top-to-bottom sequence. Tiepoint specification is further clarified in the OPERATIONS and TIMING sections. The TIEPOINT parameter must be given unless an optional dataset containing the NAH, NAV, and TIEPOINT parameters is specified.(2nd optional input dataset if the dataset is generated by program MAP, optional parameter data set (see PARMS parameter) if the dataset is generated by any other program besides program MAP ).
set. Any combination of the allowable parameters may be given. If any of the parameters are given interactively, the interactive value takes precedence. LGEOM is almost always run with the PARMS parameter as the means of entering the TIEPOINT, NAH, and NAV parameters. This parameter names a VICAR PARMS file, (xvpopen type for you programmers.) Note: If the data set is generated by program MAP, it has to be entered as a second input instead of PARMS.