"Intelligent" graphics generate the overlay rectangle, which includes the whole object, from data about the graphical object.

A graphical object contains all information that is needed for the generation of an overlay.  This includes: 

• an object ID and
• the coordinates of the hotspot region which is defined by the extent and orientation of the object.

Object ID and coordinates that define an overlay usually look thus:
123; 45,80,160,100           

123:    being the ID of the hotspot (= of the object ID)  and
45, 80, 160, 100:   being the coordinates of the hotspot rectangle.

The ID of the object and the coordinates can be written into a text file that can be used as the overlay definition file.

Since the description format of the overlays is not standardized, it varies from system to system. Therefore, your graphics program in use, such as IsoDraw, might require a plug-in for the format adaptation in order to process an overlay definition file.

Corresponding to this, the vector graphic is exported as a TIFF file so it can be used directly in the catalog.