Faulty result on contour map

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Volkan Yangin 2016-11-29

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评论： Volkan Yangin 2016-12-3

data.xls

I have just created a contour map, but some values are false. I don't know where is my error? May you help me? My dataset at the attachment.

data=xlsread('data.xlsx')
  rpm=xlsread('data.xlsx','A3:A10')
  kw=xlsread('data.xlsx','B2:I2')
  bsfc=xlsread('data.xlsx','B3:I10')
  a = surf(rpm, kw, bsfc);
  [a,b] = contourf(rpm, kw, bsfc);
  clabel(a,b);
  xlabel('rpm');
  ylabel('kW');

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Walter Roberson 2016-11-30

Could you be more specific about the areas that are "false"? The only difficulty I see is the way the 250 has a branch that ends abruptly.

Which MATLAB release are you using?

Have you tried setting the figure renderer to different things, zbuffer and painters and opengl ?

Volkan Yangin 2016-11-30

For example, at 2000 rpm and 60 kw, BSFC value must be 0, but the same point on the contur graph shows this point as 350 g/kWh.

I am using MATLAB 2008 and i didn't try anything about this process.

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Answer 1

Daniel kiracofe 2016-11-30

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在 MATLAB Online 中打开

Not 100% sure what you mean by "some values are false", but I suspect that you've just transposed x and y axis. Does

a = surf(kw,rpm, bsfc);
[a,b] = contourf(kw, rpm,  bsfc)

do what you want?

If not, then please elaborate on what you don't like about the graph and what you think it should look like.

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Guillaume 2016-11-30

You should accept Daniel's answer to give him credit and to tell others that it is now solved.

A fuel consumption of 0 at high load? I want your engine! Or perhaps the BSFC should be NaN instead of 0 to indicate that the particular test point was not tested / could not be reached.

Volkan Yangin 2016-12-3