MATLAB: How to change contour level in different range

Question

Hello, I am new to Matlab.

Currently, I am plotting BSFC map using contour function.

I wanna set different levelstep instead of fixed value.

Due to fixed LevelStep, the below graph looks so ugly.

For levelList<300, I would like to set levelStep=50, and for LevelList>300, I would like to set LevelStep as 5.

Is there any way to control Level Step (Isoline) in different LevelList?

FYI, here is my code.

Thank you for your help in advance.

rawdata=xlsread('BSFC_NA2.xlsx','Sheet1','A1:I88');
RPM =rawdata(:,1);
Torque = rawdata(:,2);
bsfc = rawdata(:,3);
R100 = rawdata(:,4);
T100 = rawdata(:,5);
RPM1 =rawdata(:,6);
Torque1 = rawdata(:,7);
bsfc1 = rawdata(:,8);
% Create gridded data:
Rpmgrid = linspace(1000,max(RPM),10); 
Torquegrid = linspace(0,90,10);  
BSFCgrid = gridfit(RPM,Torque,bsfc,Rpmgrid,Torquegrid);
[c1,h1]=contour(Rpmgrid,Torquegrid,BSFCgrid,'LevelStep',5,'ShowText','on'); drawnow
set(h1.EdgePrims(h1.LevelList>0 ), 'LineStyle', 'dotted'); 
hold on 
k5=plot(R100,T100,'r','LineWidth',3)
hold on

Answer 1

[X,Y,Z] = peaks(100) ; 
figure
hold on
contour(X,Y,Z,'LevelList',-6:0.2:4)  % levels with difference 0.2 for till 4
contour(X,Y,Z,'LevelList',4:0.5:8)   % levels with difference 0.5 from 4 to 8