... A new IRAF task has been developed that automatically identifies linear (line-like) features in an image or set of images. ... In order to automatically detect linear features, the first step is to select pixels in the image (Fig. 1 , left panel) that fall within a given data value range. ... Another aspect of extended linear features is that the image space pixels that describe them are in some way adjacent to one another and have a minimum and maximum length. ...