Hi Uwe,

Thank you for such a quick reply. Trying to work with data at one instance in time is what I have been trying to do using the qwt example and some of the other examples I have found here but I think.....no, I'm sure of it....that I just don't understand how the raster is used at all. I have set up a spectrogram plot with an overall area of for example, 500 X 500 and then try to put a horizontal 'band' of say 50 pixels high by 500 pixels wide in the plot with the color intensity based on my data (contained in an array of doubles which for simplicity right now all have the same value...) and using the next neighbor sampling method described in some of the other posts. So what I'm expecting/looking for is a 500 x 50 area of some solid color based on the value of my data, and the other 500x450 area of the plot remaining the same original background color since only one rectangular subset region has been created. The actual size of the 'bands' will be some constant area per data sample received. But what I continually get is a 'rainbow' of the colors displayed in the color bar filling the entire plot area of 500x500. Everything else looks correct in the plot...scale values, colorbar legend etc...I just don't know how to set up and control how my data is plotted using the raster object. Fortunately the data rate is very slow so I don't think the refresh rate will be an issue, at least not right now. I downloaded the latest from the svn trunk per your suggestion and will definately need the help provided in those examples when I get to that point. Thanks again.

tim
tim