何时在pcolormesh上使用imshow? [英] When to use imshow over pcolormesh?

问题描述

我经常发现自己需要使用matplotlib在Python中创建热图样式的可视化文件. Matplotlib提供了几种功能，它们显然可以完成相同的操作.建议使用pcolormesh代替pcolor，但是imshow和pcolormesh之间有什么区别(从实际的角度来看，作为数据绘图仪)?互相使用时有什么优点/缺点?在哪种情况下，一个或另一个将是明显的赢家?

I often find myself needing to create heatmap-style visualizations in Python with matplotlib. Matplotlib provides several functions which apparently do the same thing. pcolormesh is recommended instead of pcolor but what is the difference (from a practical point of view as a data plotter) between imshow and pcolormesh? What are the pros/cons of using one over the other? In what scenarios would one or the other be a clear winner?

推荐答案

从根本上讲，imshow假定数组中的所有数据元素都将以相同的大小呈现，而pcolormesh/pcolor则将具有矩形元素的数据数组，其大小可能会在矩形网格上变化.

Fundamentally, imshow assumes that all data elements in your array are to be rendered at the same size, whereas pcolormesh/pcolor associates elements of the data array with rectangular elements whose size may vary over the rectangular grid.

如果您的网格元素是均匀的，则将imshow的插值设置为最近"将看起来与默认的pcolormesh显示非常相似(没有可选的X和Y args).明显的区别是imshow y轴将反转(w.r.t. pcolormesh)并保持宽高比，尽管这些特征也可以更改为类似pcolormesh输出的样子.

If your mesh elements are uniform, then imshow with interpolation set to "nearest" will look very similar to the default pcolormesh display (without the optional X and Y args). The obvious differences are that the imshow y-axis will be inverted (w.r.t. pcolormesh) and the aspect ratio is maintained, although those characteristics can be altered to look like the pcolormesh output as well.

从实际的角度来看，如果要将数据数组可视化为单元格，尤其是在矩形网格不均匀或要绘制单元格的边界/边缘时，pcolormesh更为方便.否则，如果您具有固定的像元大小，想要保持宽高比，想要控制像素插值或想要直接指定RGB值，则imshow会更方便.

From a practical point of view, pcolormesh is more convenient if you want to visualize the data array as cells, particularly when the rectangular mesh is non-uniform or when you want to plot the boundaries/edges of the cells. Otherwise, imshow is more convenient if you have a fixed cell size, want to maintain aspect ratio, want control over pixel interpolation, or want to specify RGB values directly.

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