Matlab-尝试在彩色图的每个点上使用带有网格坐标和值的向量 [英] Matlab - Trying to use vectors with grid coordinates and value at each point for a color plot

问题描述

我正在尝试使用另一个程序的输出数据在matlab中绘制颜色图.我有3个向量，分别指示x位置，y位置(均以毫秒为单位，因为这表示黑洞周围的图像)以及所需点中每个点的值(将为其指定颜色)图像.我显然不能使用pcolor，因为指示每个像素"颜色的值不在矩阵中，而且除了meshgrid之外，我不知道从矢量中创建矩阵的其他方法，但没有由于向量的大小而起作用.

I'm trying to make a color plot in matlab using output data from another program. What I have are 3 vectors indicating the x-position, y-yposition (both in milliarcseconds, since this represents an image of the surroundings of a black hole), and value (which will be assigned a color) of every point in the desired image. I apparently can't use pcolor, because the values which indicate the color of each "pixel" are not in a matrix, and I don't know a way other than meshgrid to create a matrix out of the vectors, which didn't work due to the size of the vectors.

在此先感谢您的帮助，我可能无法立即回复.

Thanks in advance for any help, I may not be able to reply immediately.

推荐答案

如果我们不对x，y坐标的排列(即非单调)和数据样本的稀疏性做任何假设，那是获得数据的最佳方法向量中的一个不错的图像是使用TriScatteredInterp.这是一个示例:

If we make no assumptions about the arrangement of the x,y coordinates (i.e. non-monotonic) and the sparsity of the data samples, the best way to get a nice image out of your vectors is to use TriScatteredInterp. Here is an example:

% samplesToGrid.m
function [vi,xi,yi] = samplesToGrid(x,y,v)

F = TriScatteredInterp(x,y,v);
[yi,xi] = ndgrid(min(y(:)):max(y(:)), min(x(:)):max(x(:)));
vi = F(xi,yi);

下面是在100x100网格上获取500个像素"样本并构建完整图像的示例:

Here's an example of taking 500 "pixel" samples on a 100x100 grid and building a full image:

% exampleSparsePeakSamples.m
x = randi(100,[500 1]); y = randi(100,[500 1]);
v = exp(-(x-50).^2/50) .* exp(-(y-50).^2/50) + 1e-2*randn(size(x));
vi = samplesToGrid(x,y,v);
imagesc(vi); axis image

如果坐标是整数值，则戈登的答案将有效，但是图像将是多余的.

Gordon's answer will work if the coordinates are integer-valued, but the image will be spare.

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