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isoimap stsdas.analysis.isophote



isoimap -- Superposes ellipses to the gray-scale image display.


isoimap image table


The isoimap task displays the original image in the gray-scale image display, and superposes ellipses on it. Ellipse data is taken from a table created by the ellipse task.

This task is a script which calls the tasks tsort and trebin in the ttools package. These tasks create a temporary table with an interpolated version of the original input table. This temporary table is then fed to the hidden task map, which creates a set of temporary files containing coordinates of ellipse points. The task is then invoked to load the image display with the original image, and finally the stplot.sgraph task uses the temporary ellipse point files to draw the ellipses.

The semi-major axis length interval to be plotted is specified by the parameters minsma and maxsma. If the fulltable parameter is set to yes, the full range of semi-major axis lengths available in the table is used instead. Care must be taken with parameters minsma and maxsma, because the trebin task can also extrapolate from the original data, and meaningless results could be generated in some cases. Linear interpolation is used. The nlevels parameter specifies the number of ellipses to be plotted, up to 10.

Parameters available in the display task can be set before running this task so that gray-scale manipulation can be controlled. There are, however, limitations in the graphics interface so the task assumes that the fill parameter is set to "yes". This also works only when the image display is square (i.e., it has an aspect ratio of 1.0).

Packages ttools, stplot, plot, images and tv must be loaded before using this task.


image [file name]
Input image to be displayed.
table [file name]
Table containing the results of isophotometry analysis (i.e., the table produced by ellipse).
(fulltable = "yes") [boolean]
Use full range of semi-major axis from table?
(minsma = 1.0) [real, min=0.0]
Minimum semi-major axis to be plotted.
(maxsma = 1.0) [real, min=1.0]
Maximum semi-major axis to be plotted.
(nlevels = 3) [integer, min=2, max=10]
Number of ellipses.
(color = "r") [string, allowed values: r | g | b | w | y]
Graphics overlay color (colors are red, green, blue, white, or yellow).
(frame = 1) [int, min=1, max=4]
Display frame to be loaded.


1. Draw three ellipses taken from an image called image and a table table. Minimum and maximum are 10.0 and 100.0, respectively.

st> isoimap  image table fulltable=no amin=10. amax=100. nlevels=3


Graphics overlay may lack precision when using image sections with stepping, due to numerical truncation effects.


This task was written by I.Busko


isoexam, ellipse, display

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