matlab - Rotating a Plot About the Y Axis -

i have vector of values want plot brightness on circle through radius of (i.e. if 0 3 1 5 i'd want circle dark @ centre, bright ring around it, darker ring, brighter ring).

to i've attempted rotate radial vector (e) around y axis, such

[x,y,z] = cylinder(e); h = surf(x,y,z), 

however i'm not doing right, appears rotating curve around x axis. i've tried swapping x , y, still rotates around x axis. appreciated.

one way rotate vector , create surface. z data of surface (your rotated vector) color coded according colormap choose, if display surface top circles @ different brightness.

if interested "top view" of surface, no need create full surface, simple pcolor job.

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example:

%% // input data (and assumptions) e=[0 3 1 5 2 7];                 nbrightness = 10 ;                      %// number of brightness levels r = (0:numel(e)) ;                      %// radius step=1 default consecutive circles                                         %// otherwise define different thickness each circle 

so if use stairs([e 0]) different brightness levels:

i had add last 0 vector "close" last level, we'll have again in solution below.

now rotate/replicate around y, color code height, , @ top:

%% // replicate profile around axis ntt = 50 ;                              %// define how many angular division plot theta = linspace(0,2*pi,ntt) ;          %// create angular divisions [rr,tt]=meshgrid(r,theta) ;             %// generate grid   z = repmat( [e 0] , ntt , 1 ) ;         %// replicate our "e" vector match grid  [xx,yy,zz] = pol2cart(tt,rr,z) ;        %// convert cartesian coordinates  pcolor(xx,yy,zz)                        %// plot colormap(gray(nbrightness))             %// make sure use "nbrightness" colors (shades of gray) caxis([0 nbrightness])  shading flat ; axis equal               %// refine view (axis ratio , "spokes" not visible) etc... colorbar axis off 

will yield following :

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note problem not defined, had take assumptions on:

• what radius each brightness circle should have ? (i made them same can modify that)
• how many brightness levels want ? (you can modify though).