Core Plot: How to set xRange/yRange with different scales?

I am wanting to use Altitude for my Y range and Distance for my X range. Currently this is what I am using:

plotSpace.xRange = [CPPlotRange 
                        plotRangeWithLocation:CPDecimalFromFloat(0.0) 
                        length:CPDecimalFromUnsignedInteger(sortedArray.count)];
plotSpace.yRange = [CPPlotRange 
                        plotRangeWithLocation:CPDecimalFromFloat(min) 
                        length:CPDecimalFromFloat((max - min))];

That doesn't set the X range correctly, becaus开发者_Python百科e it just sets it to the number of points in the array, which is about 2500. I have tried setting the xRange to to the max value in my distance array, but that really screws up the graph.

How can I have two different scales for x and y and still have the graph be correct?

Here is what it looks like when I change the xRange to be my distance, the graph goes flat:

Calculate your min and max distance and use those to set the xRange and calculate your min and max altitude and use those to set the yRange.