*plcreate* -- Defining a Region

There are three alternative ways to define a region. The optimum choice depends on the scientific application.

1.

input the region descriptor directly as a parameter to the PROS task in question e.g. imcnts

2.

write a binary file using the task plcreate. This is faster and more convenient if the same region is to be applied repeatedly.

input file: xdata$rp110590.qp

output file: rp110590.pl

  cl> xray
  xr> ximages
  xi> plcreate
  region description: c 6930 9390 240
  reference image file or 2 dims for mask:  xdata$rp110590.qp
  output mask data file [root.pl]: rp110590             # =rp110590.pl file

3.

via saoimage as described in Using SAOimage Interactively. The region is written by saoimage to an ascii text file, default name saoimage.reg and can be directly input to a PROS task. To restore the coordinates to original image coordinates see fixsaoreg.

Although the ascii output from saoimage.reg may be input directly to PROS tasks as a region descriptor, program execution is faster using the binary output of plcreate. This task may also be used to translate saoimage.reg into binary format:

input file: saoimage.reg; xdata$rp110590.qp

output file: rp110590.pl

  xi> plcreate
  region descriptor:  saoimage              # default output file from SAOimage
  reference image file or 2 dims for mask:  xdata$rp110590.qp
  output mask data file [root.pl]: rp110590                    # =rp110590.pl file

Region masks are specific to the reference file that was used to create them, and only work correctly for that file. They can be created using any of the coordinate systems available.

The following sections will include examples of the all three of these methods.