MATLAB: Plot log with factor 20

MATLABplot

Hello,

how can I plot a scale like in this picture?

Best Answer

Hello

a=1.03;
h=(a^200-a^20)/9; 
ypoints=a^(20):h:a^200;
xpoints=log(ypoints)./log(a);
figure(1)
close(1)
figure(1)
hold on
axis([0 220 -1 1])
plot([20 200],[0 0],'b-','linewidth',3)
z=0.05;
for k=1:10
plot([xpoints(k) xpoints(k)],z*[-1 1],'b','linewidth',2)
end 
text(20-1,-1.5*z,'20')
text(200-2,-1.5*z,'200')

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MATLAB: Mapping a filled circle ,like [(abs(z-1)<=1) by any mapping function

A solution that help me and maybe useful for others (with mapping funcion -(z+1)/(z-1) and -i*cos(z/2))

clear all

clc

t=0:0.1:6.3;

y=sin(t);

x=cos(t)+1;

plot(x,y);

fill(x,y,'r');

z=complex(x,y);

u=-(z+1)/(z-1)

k=-i*cos(z/2)

s=real(u);

t=imag(u);

h=real(k);

g=imag(k);

subplot(2,2,1)

title('|z-1|<1')

hold all

fill(x,y,'r')

plot([-3,3],[0,0],'k');

plot([0,0],[-3,3],'k');

axis off equal

subplot(2,2,2)

title('f(z)=-(z+1)/(z-1) answer:-1.03+0.0003j')

hold all

scatter(s,t,20,'filled')

plot([-3,3],[0,0],'k');

plot([0,0],[-3,3],'k');

axis off equal

subplot(2,2,[3,4])

title('f(z)=-j*cos(z/2)')

hold all

fill(h,g,'g')

plot([-1,1],[0,0],'k');

plot([0,0],[-1.5,0.5],'k');

axis off equal

MATLAB: Plotting Pixels of an Image and Finding Minimum Value

Hi,

From my understanding you have already done the minimum pixel value part and you are facing problem in plotting the the gray image using surf. Changing your code with the below snippet should solve the error.

%increment=1;
xpoints=1:size(gray_double,2);
ypoints=1:size(gray_double,1);
[x,y]=meshgrid(xpoints,ypoints);
figure
surf(x,y,gray_double)

Best Answer

Related Solutions

MATLAB: Mapping a filled circle ,like [(abs(z-1)<=1) by any mapping function

MATLAB: Plotting Pixels of an Image and Finding Minimum Value

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