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- 5th January 2017, 17:03 #1

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## Matlab - RCS calculation surf function

Hello,

I am calculating Radar Cross Section with matlab. My results are correct, i want to plot these results.

I have 2 input variables.

I use the "surf" function.

Following RCS values, i want to color the curve. For example, for RCS = -5 to -2, the curve will be yellow, for RCS = 10 to 20, orange, ... I don't know how to do it.

Can you help me ?

- 5th January 2017, 17:03

- 5th January 2017, 17:20 #2

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## Re: Matlab - RCS calculation surf function

On the Mathworks page I have found the following:

surf(Z,C) plots the height of Z, a single-valued function defined over a geometrically rectangular grid, and uses matrix C, assumed to be the same size as Z, to color the surface. See*Coloring Mesh and Surface Plots*for information on defining C.

- 5th January 2017, 17:20

- 6th January 2017, 13:58 #3

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## Re: Matlab - RCS calculation surf function

Thank you for your answer.

I have only values that interest me.

Now i am trying to color the curve in different part.

ex : color 1 : values between -5 and -3

color 2 : values between 3 and 5

color 3 ...

I want to keep the surf function for the curve.

- 6th January 2017, 13:58

- 6th January 2017, 14:32 #4

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## Re: Matlab - RCS calculation surf function

I do not see the problem.

- 6th January 2017, 15:11 #5

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## Re: Matlab - RCS calculation surf function

I use the surf function to display values. I want to assign colors to the curve in function of range of values. I am not sur if i had to use colormap with conditions.

- 6th January 2017, 15:11

- 6th January 2017, 17:45 #6

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## Re: Matlab - RCS calculation surf function

You can assign the "C" matrix the values you want.

This is a MATLAB script assigning red,green and blue.

Code:clear clc A=ones(25,25);%create a simple matrix with the dimension required (mXn) %Here, start changing the matrix C1 as you wish C1 = zeros(size(A)); % filling First RGB table for row=1:12 for column=1:12 C1(row,column)=1; end end for row=13:17 for column=13:17 C1(row,column)=0; end end for row=18:25 for column=18:25 C1(row,column)=0; end end C2 = zeros(size(A)); % filling Second RGB table for row=1:12 for column=1:12 C2(row,column)=0; end end for row=13:17 for column=13:17 C2(row,column)=1; end end for row=18:25 for column=18:25 C2(row,column)=0; end end C3 = zeros(size(A)); % filling Third RGB table for row=1:12 for column=1:12 C3(row,column)=0; end end for row=13:17 for column=13:17 C3(row,column)=0; end end for row=18:25 for column=18:25 C3(row,column)=1; end end %Define the 3 RGB tables with C1,C2,C3 C(:,:,1)=C1; C(:,:,2)=C2; C(:,:,3)=C3; Z = peaks(25); surf(Z,C) title('EXAMPLE')

You have to assign in each RGB table the value you want.

I have made this:

- rows 0 to 12 and columns 0 to 12 --> asign RED which means in table one is 1, in table 2 is 0 and in table 3 is 0
- rows 13 to 17 and columns 13 to 17 --> asign GREEN which means in table one is 0, in table 2 is 1 and in table 3 is 0
- rows 18 to 25 and columns 18 to 25 --> asign BLUE which means in table one is 0, in table 2 is 0 and in table 3 is 1

So it would be like this:

Color<--->Table 1<--->Table 2<--->Table 3

RED<--->1<--->0<--->0

GREEN<--->0<--->1<--->0

BLUE<--->0<--->0<--->1Last edited by CataM; 6th January 2017 at 17:50.

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