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[GREG2\]RGDATA [Name|Array_X Array_Y Array_Z] [/SUBSET NXmin NYmin
NXmax NYmax] [/VARIABLE] [/FORMAT Fmt [code]] [/INCREMENT IncX IncY]
This command optionally creates, then loads a two-dimensional map into
the Regular Grid array (to be contoured by RGMAP, plotted by PLOT...).
This is THE basic command needed for subsequent 2-dimensional treatment.
"Regular Grid" means that data is internally stored as a two-dimensional
array, thus lies on a Regularly sampled Grid. The user-provided "pixel
values" may come from various "descriptions" of such regularly sampled
(but possibly uncompletely sampled) data:
1) Three 1-dimensional arrays, say, X Y and Z, that contain Z=f(X,Y)
at regular intervals in X and Y.
2) A preexisting internal 2-D array (possibly a section of a 3D or 4D
3) An external, specially formatted, file.
For data NOT REGULARLY ("randomly") sampled, use the GREG2\RANDOM_MAP
command instead. The Regular Grid is itself a 2D SIC variable under the
name "RG". Its extrema are available in the variables RGMIN and RGMAX
(values) and RG_XMIN, RG_XMAX, RG_YMIN, and RG_YMAX (position). Once
loaded, the RG can be saved on a file with the command GREG2\WRITE.
The following command syntax is used to deduce which "description" is
- With 0 or 3 arguments, RGDATA will try to assemble Z=f(X,Y) either
from the X,Y and Z arrays (as defined by command COLUMN) or from
"Array_X Array_Y Array_Z", that should be 1D SIC variables previous-
ly created. The option /INCREMENT is used to force the X and Y sam-
pling interval to (IncX,IncY) in case of roundoff errors. Defining
twice the same pixel is an error. If a blanking value is currently
defined, non-sampled pixels will be attributed this value, which is
overriden by the Bval value of the /BLANKING option. Note that, if a
blanking value is currently defined, pixels for which X or Y are in
the blanking range are themselves blanked.
- With ONE argument (Name) following the command, Name is taken as the
name of an existing SIC 2D variable if option /VARIABLE is present.
Otherwise, Name is a specially formatted file (see HELP RGDA-
TA FILE_FORMAT) from which the Regular Grid array must be read in.
A rectangular subset of the array defined by the pixel coordinates of
the Bottom Left Corner and Top Right Corner can be selected thanks to
the /SUBSET option.