Set a property plotSymbolto draw a character at each data point. The CPTTestApp Mac version has a demo version that displays all predefined forms. If necessary, you can create your own character forms.
Implement one of the following data source methods if you need to draw different characters for some data points:
-(NSArray *)symbolsForScatterPlot:(CPTScatterPlot *)plot
recordIndexRange:(NSRange)indexRange;
-(CPTPlotSymbol *)symbolForScatterPlot:(CPTScatterPlot *)plot
recordIndex:(NSUInteger)index;
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