Question

I’d like to make semi-log graph to show my amplitude spectrum data by using Core Plot in my iOS App.
But I couldn’t find how to make it.

Does anyone know?

Answer 1

Set the scale type on the plot space:

CPTXYPlotSpace *plotSpace = (CPTXYPlotSpace *)graph.defaultPlotSpace;
plotSpace.xScaleType = CPTScaleTypeLinear; // this is the default
plotSpace.yScaleType = CPTScaleTypeLog;

You can see samples in the example apps provided with Core Plot. The axis demo in the Mac CPTTestApp uses a log axis and the Plot Gallery app has examples as well.