Linking line plot and map (geoshow) together MATLAB

Hello all:

I wish to combine the MATLAB spatial plot generated through mapping function and the line plot on the same axis scale. However, the linkprop function is not working in this case. Please suggest how to make both axis similar?

Here is my code:

figure(1);
AX1 = subplot(1,2,1);
ax=axesm('mercator','MapLatLimit',[-65 65],'MapLonLimit',[-180 180]);
f=worldmap([-60 80],[-180 180]);
h = geoshow(coast1, 'DisplayType', 'polygon','facecolor','w');
oceanColor = [.7 .8 .9];%[.5 .7 .9];
setm(ax,'FFaceColor',oceanColor);
setm(ax, 'meridianlabel', 'on', 'parallellabel', 'on');
setm(gca,'mlabelparallel',-90);
hold on;
%Define coordinates for tropical lines
yvec = -180:180;
xvec = ones(size(yvec));
geoshow(23.5*xvec,yvec,'DisplayType','Line','LineWidth',1,'LineStyle','--','Color','k'); hold on;
geoshow(-23.5*xvec,yvec,'DisplayType','Line','LineWidth',1,'LineStyle','--','Color','k'); hold on;

geoshow(35*xvec,yvec,'DisplayType','Line','LineWidth',0.8,'LineStyle','--','Color','r'); hold on;
geoshow(-35*xvec,yvec,'DisplayType','Line','LineWidth',0.8,'LineStyle','--','Color','r'); hold on;

AX2 = subplot(1,2,2);
h1 = plot(B1,X_dist(:,2),'r--','linew',0.8); hold on;
h2 = plot(B,X_dist(:,2),'r-','linew',1.8); hold on;
h3 = plot(B2,X_dist(:,2),'r--','linew',2); hold on;
set(gca,'fontsize',14,'fontname','arial');
degreetick 'y';

linkprop(AX1,'YLim');
linkprop(AX2,'YLim');

However, I am unable to adjust the size and Y-labels of both subplots. The latitudes of both subplots should match.

Answer 1

[Austin M. Weber]

Assuming that I am understanding correctly, if the y-axis of your second subplot is supposed to represent latitude values, then you can try plotting the data using the same map axes specifications as the first subplot. Although, depending on the "x" values in your second subplot you may need to normalize the values so that they fit along the axis as if they were longitude coordinates. Hopefully that makes sense. Here is an example:

load coastlines
figure(1)
subplot(1,2,1)
    ax1=axesm('mercator','MapLatLimit',[-65 65]);
    tightmap, framem
    fillm(coastlat,coastlon,'w','EdgeColor','none')
    plabel on
    hold on
    % Add tropical lines
        lonvec = -180:1:180;
        latvec = ones(size(lonvec));
        plotm( 23.5 .* latvec, lonvec, 'LineW',1.0,'LineS','--','Color','k')
        plotm(-23.5 .* latvec, lonvec, 'LineW',1.0,'LineS','--','Color','k')
        plotm( 35.0 .* latvec, lonvec, 'LineW',0.8,'LineS','--','Color','r')
        plotm(-35.0 .* latvec, lonvec, 'LineW',0.8,'LineS','--','Color','r')
    hold off
    set(gca,'Color','#03719c') % Sets background color to ocean blue
    
subplot(1,2,2) % Use the map axes specifications as the previous subplot
    ax2=axesm('mercator','MapLatLimit',[-65 65]);
    tightmap, framem
    B1 = normalize(rand(size(lonvec)),'Range',[-180 180]);
    X_dist = normalize(rand(size(B1)),'Range',[-45 45]);
    % Sort the data so that the longitudes are sequential
    [B1,idx] = sort(B1,'ascend');
    X_dist = X_dist(idx);
    % Plot your line
    plotm(X_dist,B1)
    plabel on

As you can see, the y-axis of the second subplot is now aligned with that of the first subplot.

[Poulomi Ganguli]

for subplot(1,2,2), I have latitude values and linear values, so plotm is not working. Here I attach the values as test1 excel sheet. In the code, you have both axes shown as lat-long but in my case, y is lat and x is linear. Can we scale value directly like this?

[Austin M. Weber]

The plotm function does work, but the latitude data needs to be sorted so that it is in sequential order. However, you are correct that the function assumes the "values" are in units of longitudinal degrees, and unfortunately that means when you add tick labels the values will have degree symbols next to them, which you don't want (although the values themselves will be correct).

In the code block below, I tried adding my own x-tick labels using textm, but there is probably a better way to go about this. If I think of another solution I will let you know.

% Import data from the Excel file
data = readtable('test1.xlsx','FileType','Spreadsheet');
lat = data.Latitude; 
    % Sort the latitudes
    [lat,idx] = sort(lat,'descend');
val = data.Value; 
    % Sort the corresponding values
    val = val(idx);

% Plot the data
figure
ax2=axesm('mercator','MapLatLimit',[-65 65],'MapLonLimit',[0 40]);
    tightmap, framem
      plotm(lat, val, '.-',...
          'MarkerEdgeColor','#03719c','MarkerSize',8,...
          'LineWidth', 1, 'Color', '#04a7e7')
      xlabel('Value')
      hold on
      % Add custom x-tick labels
        textm(-63.5,  1,  '0', 'HorizontalAlignment','left')
        textm(-63.5, 20, '20', 'HorizontalAlignment','center')
        textm(-63.5, 39, '40', 'HorizontalAlignment','right')
      hold off
    plabel on % Latitude tick labels