how to set color range for color in color bar

In the following color map, i want to set

<0 values set as variation in brightness in deepskyblue 0-79 interval as variation in light green

79-157 interval as variation (you are right variation in brightness) in yellow

above 157 values as variation in brightness from light red to dark red.

I want to show the value above 157 are dark in red color. This is my upper bound.

Also guide me what kind of interpolation technique matlab use to generate raster surface from point data?

Please help??

Answer 1

[Walter Roberson]

Using the color definitions from http://www.rapidtables.com/web/color/blue-color.htm and the color names that you provided:

total_len = 160;       %your description did not give an upper bound
part1_len = 79 - 0 + 1;
part2_len = 156 - 80 + 1;
part3_len = total_len - 157 + 1;
%"variations in blue"... ummm, different brightnesses of blue?
map_part1 = [zeros(part1_len,1), zeros(part1_len,1), linspace(128,255,part1_len).'];
%purple = (128,0,128), yellow = (255,255,0)
map_part2 = [linspace(128, 1, part2_len).', linspace(0, 128, part2_len).', linspace(128, 0, part2_len).'];
%red = (255,0,0), dark red = (139, 0, 0)
map_part3 = [linspace(255, 139, part3_len).', zeros(part3_len,1), zeros(part3_len,1)];
%colormaps need to be in the range 0 to 1 so divide by 255
total_map = [map_part1; map_part2; map_part3] ./ 255;

colormap(total_map);

I rather expect that you are going to be disappointed with your color choices.

[Muhammad Usman Saleem]

yes your expectation are right. Please see edit question again

Muhammad Usman Saleem

[Walter Roberson]

You need to define your lower bound in order for variations in blue to be defined up over negative values. Which value should be so dark as to be black?

[Muhammad Usman Saleem]

lower bound for negative value is -200. This has less blue color variations.I do not require dark color please

[Walter Roberson]

Look up the color entries at http://www.rapidtables.com/web/color/index.htm . Tell me the color codes you want for the beginning and end of each range of data, and the associated data ranges. Also indicate whether you are using MS Windows with MATLAB version R2014a or earlier, or if you are using a later MATLAB or a different operating system.

Note: if you are using MS Windows with MATLAB R2014a or earlier, it might not be possible to create the small ranges of values. In particular it might not be possible to create a range of red colors from 158 to 160.

Please confirm that 160 is the upper limit. Your colorbar shows up to 160, but you talk about a range of color above 157 at the same time as you say that 157 should be your upper bound. If you want color variations above 157 then you need to have at least two entries above 157, at 158 and 159. As described for the lower bound, all values above the cutoff are given the color of the last entry in the table.

[Muhammad Usman Saleem]

For

 -200< value <0 , deepskyblue   #00BFFF   rgb(0,191,255)
  0< value <78 , goldenrod   #DAA520   rgb(218,165,32)
  78<value<157,   crimson   #DC143C   rgb(220,20,60)
   157< Value ,   red   #FF0000   rgb(255,0,0)

Upper bound is 157 and i am using Window 7 with matlab2007a version.

I hope i answer the requirements well

[Walter Roberson]

You want the first range to be variations in brightness of deepskyblue. To check: does that mean that -200 should correspond to black, which is the deepest shade of deepskyblue, and that -1 should correspond to deepskyblue ?

You want the second range to be variations in brightness of goldenrod. To check: does that mean that you want the entry at 0 to be black, which is the darkest shade of goldenrod, and that 78 should correspond to goldenrod ?

You want the third range to be variations in color of crimson, brightest first. To check: does that mean that you want the entry at 78 to be crimson and the entry at 156 to be black, the darkest shade of crimson?

If the entry at 78 is to be crimson and the entry at 157 is to be red and you are to shade between them, then the range will get brighter rather than darker, as red is the brightest red.

[Muhammad Usman Saleem]

(1) correct , but -200 should be light which means it has less deepest shade and till -1 deepshyblue has its black which means it is deepest deepshyblue

(2) correct:0 should be of lightest goldenrod and 79 should be of deepest goldenrod(you call it black for goldenrod)

(3) Correct: 80 should be shown by lightest crimson and 157 should be shown by deepest crimson( you call it black in worlds)

(4) correct: <157 ( i means to say values above 157, there is no relation of this 157 with 79, please noted) should be shown by deepest red in color

Hope again answer all requirements ..

[Walter Roberson]

This might help you:

http://uk.mathworks.com/matlabcentral/answers/232457#answer_188643

[Kelly Kearney]

I'm a little confused by the changing limits and colors you mention in your original question and the comments, but as Walter mentions, this is exactly the sort of thing cptcmap.m is for:

lim = [-200 200];
cdata = [...
    -200   0   3  91   0   0 191 255   % -200-0, shades of blue
       0  21 176  26  79 150 249 123   % 0-79, shades of green
      79 255 255  20 157 206 179   1   % 79-157, shades of yellow
     157 229   0   0 200 132   0   0]; % 157+, shades of red   

dlmwrite('mycmap.cpt', cdata, ' ');

axes;
[x,y,z] = peaks(100);
z = (z - (min(z(:))))./(max(z(:)) - min(z(:)));
z = z*diff(lim) + lim(1);

pcolor(x,y,z);
shading flat;
cptcmap('mycmap', 'mapping', 'direct', 'ncol', 30*5); 
colorbar;

[Walter Roberson]

Thanks, Kelly; I had not seen your tool before you mentioned it in that other Question today.

[Muhammad Usman Saleem]

@Kelly i am using that code now

fid = fopen('jan.txt');
 C = textscan(fid, '%f %f %f')
 fclose(fid);
 f = {'lat', 'long', 'temp'}
 S = cell2struct(C,f,2);
 N = 100;
 [Xi, Yi] = meshgrid(linspace(60,80,N),linspace(20,40,N));
 Ci = griddata(S.long, S.lat, S.temp, Xi, Yi);
 f = figure; set(f, 'Renderer', 'painters')
 colormap default
  h = geoshow(Yi,Xi,Ci,'DisplayType','surface');
 set(h,'ZData', zeros(size(get(h,'XData'))));
 p = geoshow('PAK_adm1.shp', 'DisplayType','polygon','FaceColor','none','EdgeColor','w');
 xlim([60.5 78.5]);
ylim([22.5 38.5]);
xlabel('LONGITUDE');
ylabel('LATITUDE');
title('JANUARY');
set(gca,'CLim',[0,200])
 lim = [-200 200];
cdata = [
    -200   0   3  91   0   0 191 255   % -200-0, shades of blue
       0  21 176  26  79 150 249 123   % 0-79, shades of green
      79 255 255  20 157 206 179   1   % 79-157, shades of yellow
     157 229   0   0 200 132   0   0]; % 157+, shades of red   

dlmwrite('mycmap.cpt', cdata, ' ');

axes;
[x,y,z] = peaks(100);
z = (z - (min(z(:))))./(max(z(:)) - min(z(:)));
z = z*diff(lim) + lim(1);

pcolor(x,y,z);
shading flat;
cptcmap('mycmap', 'mapping', 'direct', 'ncol', 30*5); 
colorbar;

   text(64,28,'BALOCHISTAN','Color','w');
   text(68,25.5,'SINDH','Color','w');
   text(72,32,'PUNJAB','Color','w');
   text(61.5,36,'AFGHANISTAN','Color','w');
   text(60.5,27,'IRAN','Color','w');
   text(63,23,'ARABIAN SEA','Color','w');
   text(74.5,28,'INDIA','Color','w');
   text(76,37,'CHINA','Color','w');
   text(69.899,32.884,'F.A.T.A','Color','w');
   text(72.355,34.597,'N.W.F.P','Color','w');
   text(74,35.882,'NORTHERN AREAS','Color','w');
   text(73.754,33.969,'AZAD KASHMIR','Color','w');

and getting that error now

C = 

      [323x1 double]    [323x1 double]    [323x1 double]

f = 

      'lat'    'long'    'temp'

??? Undefined function or method 'cptcmap' for input arguments of type 'char'.

Please note that in your uploaded map , the color range for -200 to 0 is very long , is this possible , this range can be shrink and remaining range remains unchanged as in your map.Actually i have less data to be in the range of -200 to 0

Regards

[Walter Roberson]

You need to download and install http://www.mathworks.com/matlabcentral/fileexchange/28943-color-palette-tables---cpt--for-matlab