how to make a heatmap for a monthly time serie?

I have a monthly time series from jan1971 to dec 1986.

I want to make a heatmap to show the value of each month in each region.

whaen I use the heatmap structure, I should write the name of x-values. but they are192 and I can not write all of them.

xvalues = {'Jan-1971', Feb1971',..., 'Dec 1986'};

yvalues = {'A','B','C','D''};

h = heatmap(xvalues1,yvalues1,cdata1);

could you please let me know the best way to show the xvalues?

could you make the heatmap with the attached data?

Answer 1

[Kostas]

Based on the heatmap documentation

tbl = readtable('heatmap.test.xlsx');
months = categorical(tbl.Var2);
years = categorical(tbl.Var1);
xlabels = categories(months);
ylabels = categories(years);
nummonths = numel(xlabels);
numyears = numel(ylabels);

x = double(months);
y = double(years);
A = tbl.A;
cdata = accumarray([y,x],A,[numyears,nummonths],@mean,NaN);

h = heatmap(xlabels,ylabels,cdata);

[Rt Ro]

Thank you for your reply.

but I want to show the regions(A, B, C abd D) in the Y-axis and then show the values of each month (e.g. jan-1971) for each region. the x axis is month-year and the y axis is the region.

[Kostas]

Do you want something like that?

You can "play" a little with datestr to have the format you want for time

tbl = readtable('heatmap.test.xlsx');
t1 = datetime(1971,1,1);t2 = datetime(1986,12,1);
t = t1:calmonths(1):t2;t= t(:);

xlabels = string(datestr(t,12));
ylabels = {'A' 'B' 'C' 'D'};

cdata = tbl{:,3:6};

h = heatmap(xlabels,ylabels,cdata');

[Rt Ro]

Thank you so much for your help. there are 192 x-tick values on the x axis (you can see in the attachment). could you please let me know how I can show each two year on the x axis (e.g. jan-1970, jan-1972, jan-1974,....)?

[Rt Ro]

tbl = readtable('heatmap.test.xlsx');
t1 = datetime(1971,1,1);t2 = datetime(1986,12,1);
t = t1:calmonths(1):t2;t= t(:);
xlabels = string(datestr(t,12));
ylabels = {'A' 'B' 'C' 'D'};
cdata = tbl{:,3:6};
h = heatmap(xlabels,ylabels,cdata');
 cmap = redbluecmap;
newCmap = imresize(cmap, [64, 3]);  % original color map contain just 11 colors, this increase it to 64
newCmap = min(max(newCmap, 0), 1);
 h.Colormap = flipud(newCmap);
set(h,'XTick',datetime('Jan-1971'):calmonths(12):datetime('Dec-1986'),'FontName', 'Times New Roman','fontsize',12);

I added the last code to show each two years on the x axis. it didn't work.

could you please help me?

[Kostas]

Unfortunately i do not know how/if this can be done in heatmap. One solution could be to save the image in vector format and then change the labels you want using an image proseccing software.

Something else you could do so as to seem nicer, it would be to make a heatmap for each month seperately.

For example to get just for January you could change the "xDisplayData" as follow

xDisplay = h.xDisplayData;
Jan = xDisplayData(1:12:end);
h.xDisplayData = Jan;

And you can do the same for the rest of the months

% February
Feb = xDisplayData(2:12:end);
h.xDisplayData = Feb;

[Rt Ro]

Thank you so much.

another person helped me with this code:

idx = month(t)==1; % index of datetime values to show as x tick

h.XDisplayLabels(~idx) = {''}; % replace rejected tick labels with empties

it works well:)

Answer 2

[Sean de Wolski]

Convert your x values to datetime. Then heatmap will just work:

dt = datetime('now'):hours(1):datetime('tomorrow');
v = rand(10,numel(dt));
heatmap(dt, 1:size(v,1), v)

[Rt Ro]

Thank you so much for your answer.

I considered 'now = jan-1971', 'tomorrow = dec-1986' and 365 instead of hours(1). but it didn't work and I have this error:

"Number of x values must equal the number of columns in 'ColorData'"

could you please help me?

[Rt Ro]

I could solve the problem but because of many x-values I have this figure.

I don't know hos I can show it better.

could you please help me?

[Sean de Wolski]

dt = datetime('now'):hours(1):datetime('tomorrow');
v = rand(2,numel(dt));
y = ["Hello" "World"];
heatmap(dt, y, v)

[Sean de Wolski]

Do you want to bin by month? instead of by hours or days?

[Rt Ro]

Yes I want to show it by month. I could do it. Now, there are a lot of xdisplay labels (192) and I am trying to show each two year on the x axis not each month. Do you have any idea?