How can i use scatter with an image

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Alex
Alex 2017-5-24
评论： Alex 2017-5-24
I have had either all the points plot correctly the colors distorted/scaled by the image they were plotted over, OR the scatter plot colors scaled correctly, but plotted incorrectly.
This produces Fig 1
figure, imshow(img, 'InitialMag',100, 'Border','tight'), hold on
scatter(mx, my, pointsize, TEC)
hold off
This gives Fig 2:
figure
ax = gca();
scatter(mx, my, pointsize, TEC)
freezeColors(ax);
hold(ax, 'on');
imz = imshow(img, 'InitialMag',100, 'Border','tight');
hold(ax, 'off')
uistack(imz, 'bottom')
  2 个评论
KSSV
KSSV 2017-5-24
There is a miss match with the scatter points data and image data....you must tell what you are expecting?
Alex
Alex 2017-5-24
I want the positions of the scatter points to remain the same as Fig 1, but want the color scale to be frozen like in Fig 2. Fig 3 shows to coordinates of the scattered points. The image coordinates are shown in Fig 4.

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回答（1 个）

Walter Roberson
Walter Roberson 2017-5-24
Your (x, y) coordinates have both positive and negative y. However, by default images are assigned positive coordinates by row and column offsets.
You should use the imshow() XData and YData options to place the image within the x y coordinate space. You will probably need to look at the documentation of image() to understand XData and YData.
  1 个评论
Alex
Alex 2017-5-24
I took a look at the documentation but all it really tells me is that, "Y-axis limits of nondefault coordinate system, specified as the comma-separated pair consisting of 'YData' and a two-element vector. The value can have more than two elements, but imshow uses only the first and last elements.
Example: 'YData',[100 200]"
since my x and y data are latitude and longitude, I try:
imz = imshow(img, 'InitialMag',100, 'Border','tight', 'XData',[0 360], 'YData',[-90 90]);
This gives Fig 5.

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