1. INTERACTIVE ISOPHOTE FITTING CURSOR OPTIONS

?          help
a          define semi-major Axis length and position angle
c          Continue fitting in non-interactive mode, disable plotting
d          Discard current isophote, go to next
f          re-Fit and plot current isophote, do not write to file yet
g          Give up: discard current isophote, go inwards
h          continue fitting and plotting in non-interactive mode
i          go Inwards, fit next isophote
m          Mask square pixel area / region under cursor
n          write current isophote, fit and plot Next isophote
o          zoom Out (display fresh image, reset zoom)
p          Plot current isophote
q          Quit
r          Roam (re-display with centering)
u          Un-mask square pixel area / region under cursor
x          cursor position marks isophote center
z          Zoom in

2. INTERACTIVE ISOPHOTE FITTING COLON COMMANDS

The algorithm parameters are listed or set with the following commands,
which may be abbreviated.  To list the current value of a parameter type
the command alone. 

:show [file]		Show current isophote parameters
:maxit [value]		Set/show maximum number of iterations
:minit [value]		Set/show minimum number of iterations
:integrmode [value]	Set/show the integration mode (bi-linear|mean|median)
:minsma [value]		Set/show the minimum semi-major axis length to fit
:maxsma [value]		Set/show the maximum semi-major axis length to fit
:step [value]		Set/show the semi-major axis grow/shrink step
:linear [yes|no]	Set/show if semi-major axis length grow/shrink linearly
:maxrit [value]		Set/show maximum semi-major axis for iterative fit
:maxgerr [value]	Set/show maximum acceptable gradient relative error
:soft [yes|no]  	Set/show soft stop flag
:cpar [value]		Set/show convergency sensitivity parameter
:sclip [value]		Set/show sigma-clip criterion
:nclip [value]		Set/show number of clipping iterations
:fflag [value]		Set/show acceptable fraction of flagged sample points
:hcenter [yes|no]	Hold ellipse center fixed ?
:hellip [yes|no]	Hold ellipticity fixed ?
:hpa [yes|no]		Hold position angle fixed ?
:x0 [value]		Set/show current center X position
:y0 [value]		Set/show current center Y position
:ellip [value]		Set/show current ellipticity
:pa [value]		Set/show current position angle
:mask [value]		Set/show current pixel mask size
:region [yes/no]	Rectangular region or square mask ?
:color [value]          Set/show current graphics color 
:dispars parameters     Set command-line parameters for display/contour tasks