I have mass flow, pressure ratio and efficiency values of about 30 points for 3 different rotation speed. I need to plot a compressor map as in the link by using these datas: https://www.uniplot.de/_images/metafiles-compressormap-80.png
I used interp1 with spline as method to create constant rotation speed lines (black lines in link above). And now i need to create efficiency isolines. I tried with different commands(for example; contour, griddata) but it did not work so far.
How can i create efficiency isolines?