AIPS NRAO AIPS HELP file for IMVAL in 31DEC18



As of Wed Jan 17 16:47:38 2018


IMVAL: Determines pixel value at specified position w messages

INPUTS

INNAME                             Image name(name).
INCLASS                            Image name(class).
INSEQ           0.0      9999.0    Image name(seq. #). 0=>high
INDISK          0.0         9.0    Disk drive #.       0=>any
PIXXY           0.0      4096.0    (X,Y,...) pixel in image
DOCENTER       -1.0         1.0    > 0 -> value at pixel
                                   else cubic interpolate
         @     Output adverbs
PIXVAL   @                         Intensity at PIXXY.
COORDINA @                         Coordinates at pixel
ERROR    @                         > 0 => fit failed, else okay

HELP SECTION

IMVAL
Type: Verb
Use: IMVAL does a cubic interpolation of the image value at the image
     location specified by PIXXY (in pixels) and returns the value in
     PIXVAL.  The coordinate is also returned.  It reports the pixel
     position, pixel value, and coordinates at message level 5.  Verb
     QIMVAL is faster since it does not report the results.
Adverbs (input):
  INNAME......Image name(name).        Standard defaults.
  INCLASS.....Image name(class).       Standard defaults.
  INSEQ.......Image name(seq. #).      0 => highest.
  INDISK......Disk drive # of image.   0 => any.
  PIXXY.......(X,Y,...) pixel location in image.  NOT zero
              on the X and Y axes anyway.
  DOCENTER....> 0 => find value at closest pixel to PIXXY
              <= 0 => do a cubic interpolation about PIXXY
Adverbs (output):
  PIXVAL......Intensity at this pixel.
  COORDINA....The X and Y coordinates are found as:
              Xpos = abs(CO(1)) + abs(CO(2))/60 + abs(CO(3))/3600
                 if any of CO(1), CO(2), CO(3) < 0: Xpos = -Xpos
              Ypos = abs(CO(4)) + abs(CO(5))/60 + abs(CO(6))/3600
                 if any of CO(4), CO(5), CO(6) < 0: Ypos = -Ypos
              Note that, although these are most suited to RA, Dec in
              sexagesimal notation, they can be used for any type of
              coordinate.  The units are standard FITS units (e.g
              degrees, m/sec, Hz, sec, etc.) except that right
              ascensions are in hours of time.
  ERROR.......If the verb is not aborted for error, but the
              interpolation fails, ERROR will be TRUE (1), else
              it will be FALSE (-1).

EXPLAIN SECTION


AIPS