isophote: Elliptical isophote image analysis.

• bmodel: Build a model image from isophotal analysis data.
• ellipse: Fit elliptical isophotes.
• isoexam: Plot ellipses on the image display (interactive).
• isoimap: Plot ellipses superposed over the gray-scale image display.
• isomap: Plot ellipses superposed over image contours.
• isopall: Plot summary of all results from isophotal analysis.
• isoplot: Plot results of isophotal analysis.
• controlpar: Set algorithm control parameters (pset).
• geompar: Set geometry-related parameters (pset).
• magpar: Set magnitude scale parameters (pset).
• samplepar: Set image sampling control parameters (pset).

This package contains tasks which perform elliptical isophote analysis. The main task is 'ellipse', which fits a set of elliptical isophotes over an image. The algorithm is closely based on the description given by Jedrzejewski (Mon.Not.R.Astr.Soc., 226, 747, 1987). The output of isophote fitting is a ST4GEM table.

The table containing isophote information is used as input by the remaining tasks in this package. Task 'bmodel' reads the table and builds an artificial image with a photometric model of the original image.

Task 'isoplot' can be used to quickly examine, in graphic form, the run of any isophote parameter against ellipse semi-major axis. Task 'isopall' builds a graphic mosaic simultaneously showing the run of nine isophote parameters against ellipse semi-major axis. Task 'isomap' draws a contour map of the original image, and superposes on it the ellipses corresponding to the contoured levels. In an analogous way, task 'isoimap' superposes ellipses on the gray-scale image display. Task 'isoexam' can be used to visually inspect the results of a fit, reading ellipses directly from the table, superposing them either on the image display or the contour graphics, and enabling user interaction through the image/graphics cursor.