How to plot multiple year data over common months?

Question

JMSE 2022-1-5

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1622835-how-to-plot-multiple-year-data-over-common-months

评论： JMSE 2022-1-6

采纳的回答： Walter Roberson

Test.xlsx

在 MATLAB Online 中打开

Dear all,

how to plot data from multiple years over one common x-axis? I have some test data measured in january over 4 years, and I want to color the data corresponding the different years. This testdata (datetime data & measurement data) containts data for January only, however future measurements may contain other months, too. So I would like to have x.axis ticks 1-12 (months) and user a scatterplot(?) to mark the points corresponding to n years (colormarker). Please find the test data attached and many thanks for help in advance!

dt=readtable("Test.xlsx");

plot (dt.Date, dt.NO2,"r.")

1 个评论
显示 -1更早的评论隐藏 -1更早的评论

Star Strider 2022-1-5

Please provide more data. There is only one month (January) for all four years in that file excerpt.

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

Walter Roberson 2022-1-5

1
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/1622835-how-to-plot-multiple-year-data-over-common-months#answer_868660

在 MATLAB Online 中打开

With different markers as well as different colors (different colors alone is easier.)

filename = 'https://www.mathworks.com/matlabcentral/answers/uploaded_files/853865/Test.xlsx';

dt = readtable(filename);

[y, m, d] = ymd(dt.Date);

baseyear = min(y);

lastyear = max(y);

cmap = colormap(jet(lastyear-baseyear+1));

G = y - baseyear + 1;

x = datetime(baseyear, m, 1, 'Format', 'MM');

pointsize = 30;

markers = {'.', '+', '*', '<', 'o', 's'}.';

assert(length(markers) >= max(G), 'Need more markers');

markermap = markers(G);

hold on

splitapply(@(M,NO2,c,mark) scatter(M, NO2, pointsize, c(1,:), mark{1}), x, dt.NO2, cmap(G,:), markermap, G);

%scatter(x, dt.NO2, pointsize, cmap(y-baseyear+1,:));

hold off

xlim auto; ylim auto;

ax = gca; ax.XRuler.TickLabelFormat = 'MMM';

xticks(datetime(baseyear,1:12,1))

8 个评论
显示 6更早的评论隐藏 6更早的评论

JMSE 2022-1-5

在 MATLAB Online 中打开

Test.xlsx

I have modified your code in order to see the different days within the single months:

dt=readtable("Test.xlsx");

d = day(dt.Date,'dayofmonth');

m = month(dt.Date);

y = year(dt.Date);

baseyear = min(y);

lastyear = max(y);

cmap = colormap(jet(lastyear-baseyear+1));

x = datetime(baseyear, m, d, 'Format', 'MM:dd');

pointsize = 30;

hold on

scatter(x, dt.NO2, pointsize, cmap(y-baseyear+1,:));

hold off

ax = gca; ax.XRuler.TickLabelFormat = 'MMM DD';

xticks(datetime(baseyear,1:12,1))

axis(ax, 'tight')

xlim(ax, xlim(ax) + [-1,1]*range(xlim(ax)).* 0.05)

ylim([0 5])

title ("title")

ylabel ("title")

legend

However; I still cannot add a proper legend representing the different years related to the colors. Moreover, I am still wondering how to erase the note '2017-2018' in the lower corner. I understand this is an artefact of how one has to trick matlab to plot multiple years over one year, however I still do not want present this in the plot.

Many, many thanks!

JMSE 2022-1-6

Actually, would it not be simpler to split the datetime into 2 arrays (1: day and months; 2: year) and to scatter it with scatter(x = day and month, y = measurements, sz = pointsize, c = year)? However, I o not know yet how to split the datetime array into two seperate arrays, I will try to figure that out. Any hint is very welcome of course.

JMSE 2022-1-6

在 MATLAB Online 中打开

This does what I want:

dt=readtable("Test.xlsx"); 
d = day(dt.Date,'dayofyear'); 
m = month(dt.Date); 
y = year(dt.Date); 
baseyear = min(y); 
lastyear = max(y); 
cmap = colormap(jet(lastyear-baseyear+1)); 
G = y - baseyear + 1; 
scatter(d,dt.NO2,[],y) 
xlim([-.5 365.5]) 
xticks([0 31 59 90 120 151 181 212 243 273 304 334]) 
xticklabels({'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'})
ylim([0 5]) 
hold on
nG = max(G); 
L = gobjects(1, nG); 
for K = 1 : nG;
    L(K) = plot(nan, nan, 'color', cmap(K,:));
end
hold off
title ("") 
xlabel ("Months")   
ylabel ("uM nitrite") 
legend(L, string(baseyear:lastyear)) 
grid on  
box off   