MATLAB Plotting dot in a specific area over a contourfm plot - matlab

Question

I have a contourfm plot on which I want to place a dot. The contourfm plot by itself works fine with no error. But when I try to place a dot at a specific point, it overrides the contourfm plot and just places a dot on a white background without the eqdconic figure and with the latitude and longitude lines squashed together. I am using hold on and I've tried plotting the data first and plotting the dot first, but both produce the same result. Can anyone tell me what I'm doing wrong? I think maybe I should not be using 'plot' as the command.
** The code has been modified to reflect the answer. plotm was used instead of plot. the x and y values for the dot was switched to reflect MATLAB's lat, lon order (instead of lon, lat.)
% Eqdconic script
% Define figure and axes
fg1 = figure(1);
% set(fg1, 'paperposition', [0 0 8.5 8.5]);
axesm('MapProjection','eqdconic', 'MapParallels', [], 'MapLatLimit',[-80 -60],'MapLonLimit',[190 250]) % 60-70S and 120-160W
framem on; gridm on; mlabel on; plabel on; hold all;
% Old code that was incorrect:
% xValue = find(x(:,1) == 224); % Longitude closest to 136 03.56W
% yValue = find(y(1,:) == -66.75); % Latitude closest to 66 39.67S
% plot(xValue,yValue,'b.','MarkerSize',20); % Plot a black dot
% Plot dot
plotm(-66.75,224,'k.','MarkerSize',20);
hold on
% Plot data
frame = dataPoint(:,:,k);
contourfm(y,x,frame, 'LineStyle', 'none');
% Colorbar
caxis([0 100]);
h = colorbar;
ylabel(h,'Percent');
% Title: Days 1:1258 inclusive. 20100101 to 20130611
date = datenum(2009, 12, 31) + k; % Convert t into serial numbers
str = datestr(date, 'mmm yyyy');
title(str);

Answer 1

1
Use plotm instead of plot.
2
Replace this line
plot(xValue,yValue,'b.','MarkerSize',20); % Plot a black dot
with
plotm(x(xValue,1),y(1,yValue),'b.','MarkerSize',20); % Plot a black dot
Note that find returns the index of the found element not its value. However, in your case you can actually pass the actual values
3
If you will not use xValue and yValue later you can remove these lines
xValue = find(x(:,1) == 224); % Longitude closest to 136 03.56W
yValue = find(y(1,:) == -66.75); % Latitude closest to 66 39.67S
and change the plotting line to
plotm(224,-66.75,'b.','MarkerSize',20); % Plot a black dot
4
However this will not plot the dot because the latitude and longitude are swapped comparing to the ranges you have mentioned in axesm command. But since you use contourfm(y,x), I assume there should be swapped so the plotting line will be
plotm(-66.75,224,'b.','MarkerSize',20); % Plot a black dot
5
which gives us a blue dot, so we change the color to black by using 'k.' instead of 'b.' and we have
% Eqdconic script
% Define figure and axes
fg1 = figure(1);
% set(fg1, 'paperposition', [0 0 8.5 8.5]);
axesm('MapProjection','eqdconic', 'MapParallels', [], 'MapLatLimit',[-80 -60],'MapLonLimit',[190 250]) % 60-70S and 120-160W
framem on; gridm on; mlabel on; plabel on; hold all;
plotm(-66.75,224,'k.','MarkerSize',20); % Plot a black dot
which produces