The user is required to enter the size of the sampling area and the pixel size in arc secs. This is used to define the width of pixel template radius employed. It is assumed that pixels are the same size in the x and y directions.
The skewness value assigned to each pixel of the output image is calculated using the values of pixel count found for all the non-bad pixels within the calculated radius. The value obtained is multiplied by 1000 (or a user defined value) to make display easier.
The modal count value used during the calculation is either the global value (defined by the user) or a local value calculated as required.
The resultant value is some measure of the extent to which the pixel count values surrounding a given pixel are not distributed in a Gaussian manner.
A border is present in the final output image which is the same width as the radius of the template used. Pixels within the border have been assigned the value bad.
ESP --- Extended Surface Photometry