How can you get the x and y values from plotted points on a quiver plot?

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Sancheet Hoque
Sancheet Hoque 2016-11-17
评论： Sancheet Hoque 2016-11-18
I have quiver plots in which I used longitude and latitude for x and y and vectors that are u and v. I was wondering if there is anyway to extract all of these points in Matlab. I know code below gives me a range, but I want the specific x and y values and the corresponding u and v. I want these values so I can compare and receive more information from another data set
xLimits = get(gca,'Xlim');
yLimits = get(gca,'Ylim');

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采纳的回答

Greg Dionne
Greg Dionne 2016-11-17
You'll want to get the line handle.
Something like:
>> hq = quiver([1 2 3],[3 1 2],[4 1 5],[2 1 2])
hq =
Quiver with properties:
Color: [0 0.4470 0.7410]
LineStyle: '-'
LineWidth: 0.5000
XData: [1 2 3]
YData: [3 1 2]
ZData: []
UData: [4 1 5]
VData: [2 1 2]
WData: []
Once you have the handle, you can reference the properties either via "get" or direct property access:
>> get(hq, 'XData')
ans =
1 2 3
In more recent versions of MATLAB you can use direct property access:
>> hq.XData
ans =
1 2 3
Don't have the handle? You can search for it:
>> hq = findobj(gca,'Type','quiver')
hq =
Quiver with properties:
Color: [0 0.4470 0.7410]
LineStyle: '-'
LineWidth: 0.5000
XData: [1 2 3]
YData: [3 1 2]
ZData: []
UData: [4 1 5]
VData: [2 1 2]
WData: []
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Greg Dionne
Greg Dionne 2016-11-18
If you want to find all the values that aren't NaN, you can do something like:
x = hq.XData;
y = hq.YData;
u = hq.UData;
v = hq.VData;
% get rid of any nan
idxgood = ~(isnan(x) | isnan(y) | isnan(u) | isnan(v));
x = x(idxgood);
y = y(idxgood);
u = u(idxgood);
v = v(idxgood);
Not sure if that's what you meant, but give it a whirl and let us know.
Sancheet Hoque
Sancheet Hoque 2016-11-18
THANK YOU so much, I should've asked here from the beginning instead of straining my brain!

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更多回答（1 个）

Chad Greene
Chad Greene 2016-11-17
If you can get a handle from when the quiver plot was created, it's easy:
[x,y] = meshgrid(0:0.2:2,0:0.2:2);
u = cos(x).*y;
v = sin(x).*y;
h = quiver(x,y,u,v);
then the x data can be obtained by
X = get(h,'Xdata');
and the y data is obtained by the same method. If you don't already have a handle for the quiver plot, you can try to find it by
get(gca,'Children')

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