I wrote my osn set of utility functions for my own use for these sorts of problems. The approach I use here is to find the normalised coordinates of the point, and use the ‘left’ and ‘lower’ legend position values to draw the annotation arrow.
Try this —
xp = 34573;
yp = 89832;
p = plot(xp,yp,'o','MarkerFaceColor','b');
lgd = legend(p);
lgdpos = lgd.Position;
xapf = @(x,pos,xl) pos(3)*(x-min(xl))/diff(xl)+pos(1); % 'x' Annotation Position Function
yapf = @(y,pos,yl) pos(4)*(y-min(yl))/diff(yl)+pos(2); % 'y' Annotation Position Function
xl = xlim;
yl = ylim;
pos = gca().Position;
pointpos = [xapf(xp,pos,xlim), yapf(yp,pos,ylim)];
annotation('arrow', [pointpos(1) lgdpos(1)], [pointpos(2) lgdpos(2)])
Make appropriate changes to get the result you want.
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