Another way to access the data base is using the graphic tasks. These tasks require a graphic device (from Tektronix 4010 to Work Station) and use an user interface based on a command language. With these tasks the user can draw maps in different scales and projection types, plot the objects and , finally, can also know the values of the physical parameters of the objects (catalogue fields) by pointing the cursor. He can plot wedge diagrams, histograms, pie-charts and regression lines between two variables. Moreover the user can plot overlay maps in the same scale of his plates to identify the plates objects.
See chapter for an explanation of the graphic tasks.