Matplotlib的imshow偏移量以匹配轴? [英] Matplotlib imshow offset to match axis?

问题描述

我正在使用matplotlib.pyplot.scatter绘制一堆UTM坐标.我还有一张背景空气照片，据我所知与背景图的范围完全吻合.当我绘制数据并设置轴时，可以正确显示散点图.如果我使用imshow绘制空中照片，它将使用像素数作为轴位置.我需要将图像(numpy数组)移动到正确的UTM位置.有任何想法吗?我对matplotlib和numpy相当陌生.

I'm plotting a bunch of UTM coordinates using a matplotlib.pyplot.scatter. I also have a background air photo that I know matches the extent of the figure exactly. When I plot my data and set the axis I can display the scatter correctly. If I plot the air photo using imshow it uses the pixel number as the axis location. I need to shift the image (numpy array) to it's correct UTM position. Any ideas? I'm fairly new to matplotlib and numpy.

例如:我知道图像的左上角(imshow坐标:0,0)具有UTM坐标(269658.4、538318.2).我该如何告诉imshow同一件事?

For example: I know that the top left corner of the image (imshow coordinate: 0,0) has the UTM coordinate (269658.4, 538318.2). How do I tell imshow the same thing?

我还应该说我调查了底图，但它似乎尚未完全支持UTM.我的学习区域很小.

I should also say that I investigated Basemap but it doesn't appear to fully support UTM yet. My study area is very small.

推荐答案

您需要使用extent关键字参数来显示.

You need to use the extent keyword argument to imshow.

作为一个简单的例子:

import numpy as np
import matplotlib.pyplot as plt

# Random points between 50000 and 51000
x, y = 1000 * np.random.random((2, 10)) + 50000

# A 10x10 "image"...
image = np.arange(100).reshape((10,10))

# In a lot of cases, image data will be "flipped" vertically, so you may need 
# use the `origin` kwarg, as well (or just swap the ymin and ymax ordering).
plt.imshow(image, extent=[x.min(), x.max(), y.min(), y.max()])
plt.plot(x, y, 'ro')

plt.show()

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