I think you have two choices here: 1) Not mind that your XY coordinates are considered vertices by IDL and, thus, be happy with continuing to use IDLgrPolyline. For this you need an IDLgrView with a VIEWPLANE_RECT that is the exact size of your coordinate system and an IDLgrWindow with that exact size as well. After this, I would think that this polyline would display your symbols at precisely the XY locations you want. Are you getting different results than this? Or is there another reason why you would rather that your XY points not be considered to be vertices? 2) Let your XY points be represented on an IDLgrImage that is the size of your coordinate system. You would then simply have to decide how to display the symbol representing these points. If the symbol is a single-pixel dot of color or a square of the 8 pixels surrounding the XY points, then this display is trivial. If, however, it is more complicated, like a circle, then the algorithm for coloring the pixels of the IDLgrImage would probably be more unpleasant than going with option 1 above. James Jones