MATLAB 颜色图函数（imagesc/scatter/polarPcolor/pcolor）
olivermahout 人气:02维的热度图 imagesc
imagesc（x, y, z），x和y分别是横纵坐标，z为值，表示颜色
1 imagesc(theta,phi,slc); colorbar
2 xlabel('theta(°)','fontname','Times New Roman','FontSize',14);
3 ylabel('phi(°)','fontname','Times New Roman','FontSize',14);
4 sta = '3 objects at (θ,φ,r) : (-30,30,1) (0,0,2) (60,-60,0.5)';
5 str=sprintf(strcat('3D Imaging Slice at :', num2str(d_max*D/N), '(m)', '\n',sta));
6 title(str, 'fontname','Times New Roman','Color','k','FontSize',13);
7 grid on
其中，colorbar的坐标值调整：caxis([0 1]);
colormap的色系调整：colormap hot
3维散点图 scatter
1 scatter3(x,y,z,24,c,'filled'); 2 % axis([-(R+2) (R+2) -(R+2) (R+2) 0 (h+2)]); 3 colorbar
2维 极坐标热度图 polarPcolor
polarPcolor(R_axis, theta, value)，前两个为半径方向坐标轴和圆心角坐标轴，value为值，用颜色表示
1 [fig, clr] = polarPcolor(R_axis, theta, x_d_th, 'labelR','range (m)','Ncircles', 5,'Nspokes',7); 2 colormap hot 3 % caxis([0 1]);
其中polarPcolor代码如下：
1 function [varargout] = polarPcolor(R,theta,Z,varargin)
2 % [h,c] = polarPcolor1(R,theta,Z,varargin) is a pseudocolor plot of matrix
3 % Z for a vector radius R and a vector angle theta.
4 % The elements of Z specify the color in each cell of the
5 % plot. The goal is to apply pcolor function with a polar grid, which
6 % provides a better visualization than a cartesian grid.
7 %
8 %% Syntax
9 %
10 % [h,c] = polarPcolor(R,theta,Z)
11 % [h,c] = polarPcolor(R,theta,Z,'Ncircles',10)
12 % [h,c] = polarPcolor(R,theta,Z,'Nspokes',5)
13 % [h,c] = polarPcolor(R,theta,Z,'Nspokes',5,'colBar',0)
14 % [h,c] = polarPcolor(R,theta,Z,'Nspokes',5,'labelR','r (km)')
15 %
16 % INPUT
17 % * R :
18 % - type: float
19 % - size: [1 x Nrr ] where Nrr = numel(R).
20 % - dimension: radial distance.
21 % * theta :
22 % - type: float
23 % - size: [1 x Ntheta ] where Ntheta = numel(theta).
24 % - dimension: azimuth or elevation angle (deg).
25 % - N.B.: The zero is defined with respect to the North.
26 % * Z :
27 % - type: float
28 % - size: [Ntheta x Nrr]
29 % - dimension: user's defined .
30 % * varargin:
31 % - Ncircles: number of circles for the grid definition.
32 % - Nspokes: number of spokes for the grid definition.
33 % - colBar: display the colorbar or not.
34 % - labelR: legend for R.
35 %
36 %
37 % OUTPUT
38 % h: returns a handle to a SURFACE object.
39 % c: returns a handle to a COLORBAR object.
40 %
41 %% Examples
42 % R = linspace(3,10,100);
43 % theta = linspace(0,180,360);
44 % Z = linspace(0,10,360)'*linspace(0,10,100);
45 % figure
46 % polarPcolor(R,theta,Z,'Ncircles',3)
47 %
48 %% Author
49 % Etienne Cheynet, University of Stavanger, Norway. 28/05/2016
50 % see also pcolor
51 %
52
53 %% InputParseer
54 p = inputParser();
55 p.CaseSensitive = false;
56 p.addOptional('Ncircles',5);
57 p.addOptional('Nspokes',8);
58 p.addOptional('labelR','');
59 p.addOptional('colBar',1);
60 p.parse(varargin{:});
61
62 Ncircles = p.Results.Ncircles ;
63 Nspokes = p.Results.Nspokes ;
64 labelR = p.Results.labelR ;
65 colBar = p.Results.colBar ;
66 %% Preliminary checks
67 % case where dimension is reversed
68 Nrr = numel(R);
69 Noo = numel(theta);
70 if isequal(size(Z),[Noo,Nrr]),
71 Z=Z';
72 end
73
74 % case where dimension of Z is not compatible with theta and R
75 if ~isequal(size(Z),[Nrr,Noo])
76 fprintf('\n')
77 fprintf([ 'Size of Z is : [',num2str(size(Z)),'] \n']);
78 fprintf([ 'Size of R is : [',num2str(size(R)),'] \n']);
79 fprintf([ 'Size of theta is : [',num2str(size(theta)),'] \n\n']);
80 error(' dimension of Z does not agree with dimension of R and Theta')
81 end
82 %% data plot
83 rMin = min(R);
84 rMax = max(R);
85 thetaMin=min(theta);
86 thetaMax =max(theta);
87 % Definition of the mesh
88 Rrange = rMax - rMin; % get the range for the radius
89 rNorm = R/Rrange; %normalized radius [0,1]
90 % get hold state
91 cax = newplot;
92 % transform data in polar coordinates to Cartesian coordinates.
93 YY = (rNorm)'*cosd(theta);
94 XX = (rNorm)'*sind(theta);
95 % plot data on top of grid
96 h = pcolor(XX,YY,Z,'parent',cax);
97 shading flat
98 set(cax,'dataaspectratio',[1 1 1]);axis off;
99 if ~ishold(cax);
100 % make a radial grid
101 hold(cax,'on')
102 % Draw circles and spokes
103 createSpokes(thetaMin,thetaMax,Ncircles,Nspokes);
104 createCircles(rMin,rMax,thetaMin,thetaMax,Ncircles,Nspokes)
105 end
106
107 %% PLot colorbar if specified
108 if colBar==1,
109 c =colorbar('location','WestOutside');
110 caxis([quantile(Z(:),0.01),quantile(Z(:),0.99)])
111 else
112 c = [];
113 end
114
115 %% Outputs
116 nargoutchk(0,2)
117 if nargout==1,
118 varargout{1}=h;
119 elseif nargout==2,
120 varargout{1}=h;
121 varargout{2}=c;
122 end
123
124 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
125 % Nested functions
126 %%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
127 function createSpokes(thetaMin,thetaMax,Ncircles,Nspokes)
128
129 circleMesh = linspace(rMin,rMax,Ncircles);
130 spokeMesh = linspace(thetaMin,thetaMax,Nspokes);
131 contour = abs((circleMesh - circleMesh(1))/Rrange+R(1)/Rrange);
132 cost = cosd(90-spokeMesh); % the zero angle is aligned with North
133 sint = sind(90-spokeMesh); % the zero angle is aligned with North
134 for kk = 1:Nspokes
135 plot(cost(kk)*contour,sint(kk)*contour,'k:',...
136 'handlevisibility','off');
137 % plot graduations of angles
138 % avoid superimposition of 0 and 360
139 if and(thetaMin==0,thetaMax == 360),
140 if spokeMesh(kk)<360,
141
142 text(1.05.*contour(end).*cost(kk),...
143 1.05.*contour(end).*sint(kk),...
144 [num2str(spokeMesh(kk),3),char(176)],...
145 'horiz', 'center', 'vert', 'middle');
146 end
147 else
148 text(1.05.*contour(end).*cost(kk),...
149 1.05.*contour(end).*sint(kk),...
150 [num2str(spokeMesh(kk),3),char(176)],...
151 'horiz', 'center', 'vert', 'middle');
152 end
153
154 end
155 end
156 function createCircles(rMin,rMax,thetaMin,thetaMax,Ncircles,Nspokes)
157
158 % define the grid in polar coordinates
159 angleGrid = linspace(90-thetaMin,90-thetaMax,100);
160 xGrid = cosd(angleGrid);
161 yGrid = sind(angleGrid);
162 circleMesh = linspace(rMin,rMax,Ncircles);
163 spokeMesh = linspace(thetaMin,thetaMax,Nspokes);
164 contour = abs((circleMesh - circleMesh(1))/Rrange+R(1)/Rrange);
165 % plot circles
166 for kk=1:length(contour)
167 plot(xGrid*contour(kk), yGrid*contour(kk),'k:');
168 end
169 % radius tick label
170 for kk=1:Ncircles
171
172 position = 0.51.*(spokeMesh(min(Nspokes,round(Ncircles/2)))+...
173 spokeMesh(min(Nspokes,1+round(Ncircles/2))));
174
175 if abs(round(position)) ==90,
176 % radial graduations
177 text((contour(kk)).*cosd(90-position),...
178 (0.1+contour(kk)).*sind(86-position),...
179 num2str(circleMesh(kk),2),'verticalalignment','BaseLine',...
180 'horizontalAlignment', 'center',...
181 'handlevisibility','off','parent',cax);
182
183 % annotate spokes
184 text(contour(end).*0.6.*cosd(90-position),...
185 0.07+contour(end).*0.6.*sind(90-position),...
186 [labelR],'verticalalignment','bottom',...
187 'horizontalAlignment', 'right',...
188 'handlevisibility','off','parent',cax);
189 else
190 % radial graduations
191 text((contour(kk)).*cosd(90-position),...
192 (contour(kk)).*sind(90-position),...
193 num2str(circleMesh(kk),2),'verticalalignment','BaseLine',...
194 'horizontalAlignment', 'right',...
195 'handlevisibility','off','parent',cax);
196
197 % annotate spokes
198 text(contour(end).*0.6.*cosd(90-position),...
199 contour(end).*0.6.*sind(90-position),...
200 [labelR],'verticalalignment','bottom',...
201 'horizontalAlignment', 'right',...
202 'handlevisibility','off','parent',cax);
203 end
204 end
205
206 end
207 end
再贴一个示例代码：
1 %% Examples 2 % The following examples illustrate the application of the function 3 % polarPcolor 4 clearvars;close all;clc; 5 6 %% Minimalist example 7 % Assuming that a remote sensor is measuring the wind field for a radial 8 % distance ranging from 50 to 1000 m. The scanning azimuth is oriented from 9 % North (0 deg) to North-North-East ( 80 deg): 10 R = linspace(50,1000,100)./1000; % (distance in km) 11 Az = linspace(0,80,100); % in degrees 12 [~,~,windSpeed] = peaks(100); % radial wind speed 13 figure(1) 14 [h,c]=polarPcolor(R,Az,windSpeed); 15 16 %% Example with options 17 % We want to have 4 circles and 7 spokes, and to give a label to the 18 % radial coordinate 19 20 figure(2) 21 [~,c]=polarPcolor(R,Az,windSpeed,'labelR','r (km)','Ncircles',7,'Nspokes',7); 22 ylabel(c,' radial wind speed (m/s)'); 23 set(gcf,'color','w') 24 %% Dealing with outliers 25 % We introduce outliers in the wind velocity data. These outliers 26 % are represented as wind speed sample with a value of 100 m/s. These 27 % corresponds to unrealistic data that need to be ignored. To avoid bad 28 % scaling of the colorbar, the function polarPcolor uses the function caxis 29 % combined to the function quantile to keep the colorbar properly scaled: 30 % caxis([quantile(Z(:),0.01),quantile(Z(:),0.99)]) 31 32 windSpeed(1:10:end,1:20:end)=100; 33 34 figure(3) 35 [~,c]=polarPcolor(R,Az,windSpeed); 36 ylabel(c,' radial wind speed (m/s)'); 37 set(gcf,'color','w') 38 39 %% polarPcolor without colorbar 40 % The colorbar is activated by default. It is possible to remove it by 41 % using the option 'colBar'. When the colorbar is desactivated, the 42 % outliers are not "removed" and bad scaling is clearly visible: 43 44 figure(4) 45 polarPcolor(R,Az,windSpeed,'colBar',0) ; 46 47 48 %% Different geometry 1 49 N = 360; 50 R = linspace(0,1000,N)./1000; % (distance in km) 51 Az = linspace(0,360,N); % in degrees 52 [~,~,windSpeed] = peaks(N); % radial wind speed 53 figure(5) 54 [~,c]= polarPcolor(R,Az,windSpeed); 55 ylabel(c,' radial wind speed (m/s)'); 56 set(gcf,'color','w') 57 %% Different geometry 2 58 N = 360; 59 R = linspace(500,1000,N)./1000; % (distance in km) 60 Az = linspace(0,270,N); % in degrees 61 [~,~,windSpeed] = peaks(N); % radial wind speed 62 figure(6) 63 [~,c]= polarPcolor(R,Az,windSpeed,'Ncircles',3); 64 location = 'NorthOutside'; 65 ylabel(c,' radial wind speed (m/s)'); 66 set(c,'location',location); 67 set(gcf,'color','w')
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