% @(#)apply_map.hlq	17.1.1.1 (ESO-IPG) 01/25/02 17:43:15 
%++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
%.COPYRIGHT  (c)  1990 European Southern Observatory
%.IDENT      apply_map.hlq
%.AUTHOR     KB, IPG/ESO
%.KEYWORDS   MIDAS, help files, APPLY/MAP
%.PURPOSE    On-line help file for the command: APPLY/MAP
%.VERSION    1.0  12-NOV-1987 : Creation, KB
%----------------------------------------------------------------
\se
SECTION./MAP
\es\co
APPLY/MAP					12-NOV-1987  KB
\oc\su
APPLY/MAP outframe = inframe mapframe control_flags
	use an image frame like a Lookup Table
\us\pu
Purpose:      
           use an image frame like a Lookup Table
\up\sy
Syntax:       
           APPLY/MAP outframe = inframe mapframe control_flags
\ys\pa
           outframe = output frame
\ap\pa
           inframe  = input frame
\ap\pa
           mapframe = 1-dim frame which serves as a pseudo LookupTable
\ap\pa
           control_flags = two variables controlling
\\
              (1) mapping of input pixels with intensities outside the coord.
                  space of the map frame,
\\
                  0: map these pixels to start and end of map frame
\\
                  1: leave these pixels unchanged
\\
              (2) indicating equidistant or other coord.space of map frame
\\
                  0: 1-dim map frame, coord.space defined by descriptor
                     START and STEP
\\
                  1: 2-dim map frame, 1. line holds map coords, 2. line holds
                     map intensities
\\
                  2: 2-dim map frame, 1. line holds valid intervals, 2. line
                     holds map intensities for endpoints of intervals 
                     (in between interpolation);
\\
              defaulted to 0,0
\ap\sa
See also:
           COMPUTE/IMAGE, REPLACE/IMAGE, LOAD/LUT
\as\no
Note:         
           The intensity of each pixel of the input frame is interpreted as a
           world coordinate, `wx' in the coordinate space of the mapframe.
\\
           The corresponding output pixel will either have the intensity of the
           pixel in the mapframe with coords closest to `wx' or will be
           interpolated from the intensities of the enclosing coords interval.
\on\exs
Examples:
\ex
           APPLY/MAP new = old lut
            Map frame `old.bdf' via 1-dim frame `lut.bdf' to obtain result
            frame `new.bdf'. Descriptors START + STEP of `lut.bdf' determine
            mapping index.
\xe\ex
           APPLY/MAP new = old lut 1,0
            As above, but all pixels with an intensity < start_map or > end_map
            are left unmapped (i.e. unchanged).
\xe\ex
           APPLY/MAP new = old lut 0,1
            Determine corresponding map pixel from map coordinate which is
            closest to input pixel intensity. `lut.bdf' is a 2-dim frame, first
            line holds mapping coords. and second line mapping intensities.
\xe\ex
           APPLY/MAP new = old lut 0,2
            Find map coordinate interval which contains input pixel intensity,
            and interpolate output pixel from corresponding map intensities.
            `lut.bdf' is a 2-dim frame, first line holds mapping coords.
            intervals (there may be holes where nothing is changed) and second
            line holds mapping intensities for endpoints of the intervals.
\xe \sxe