The normalized coordinate can be calculated with basic math: normalizedX = event.X / wDrawWidth normalizedY = event.Y / wDrawHeight In most applications WIDGET_DRAW dimensions are static, so those 'windowWidth' and 'windowHeight' values are easy to acquire. If, however, your WIDGET_DRAW dimensions can change dynamically, a programmer can query them dynamically with call syntax like: wDrawGeometry = widget_info(wDraw, /GEOM) wDrawWidth = wDrawGeometry.XSIZE wDrawHeight = wDrawGeometry.YSIZE The above code is an option for dynamically-size draw windows, but I would actually recommend maintaining 'wDrawWidth' and 'wDrawHeight' variables and updating them every time you handle any resize event. James Jones

You will probably want to use the IDLgrWindow::PickData method to return your normalized coordinate position. It's not clear from your description if you're normalizing the data in the IDLgrPlot, or if you're scaling your container IDLgrModel to cause the normalization. I'll assume it's the latter, since that makes life simpler. I'm also going to assume that you've stored your IDLgrView as the GRAPHICS_TREE property of the IDLgrWindow, otherwise you'll need to get your IDLgrView reference ("oview") by "some other means". Here's some example code for extracting the data coordinates from the plot in your event handler. widget_control, event.id, get_value = odrawwindow odrawwindow->getproperty, graphics_tree = oview omodel = oview->get(position = 0) oplt = omodel->get(position = 0) r = odrawwindow->pickdata(oview, oplt, [event.x, event.y], xyz, pick_status = ps) if (ps eq 1) then begin datax = xyz[0] datay = xyz[1] endif If you are normalizing your data *before* you populate the IDLgrPlot object, then datax and datay will be in normalized coordinates and you will want to perform an additional mathematical inversion to convert back to lat/long. realdatax = datax*xscaleinversion + xoffset realdatay = data*yscaleinversion + yoffset Jim.