将ASCII表转换为FITS图像 [英] Converting ASCII Table to FITS image

问题描述

我是该领域的初学者.我有一个包含三列的文本文件:X，Y，在(X，Y)处的强度.它们基本上是数组(1X10000)，每个数组都通过python写到文本文件中.要在python中绘制数据集，我可以简单地使用trisurf来实现. 但是，为了进行进一步处理，我需要从中创建合适的图像. 如何从该文本文件中制作FITS图像(而不是简单的FITS表)(最好通过python或matlab).

I am a beginner in this domain. I have a text file having three columns: X, Y, Intensity at (X, Y). They are basically arrays (1X10000) each written out in a text files via python. To plot the dataset in python, I can simply use trisurf to achieve this. But for further processing, I need to create a fits image from it. How do I make FITS image (and NOT a simple FITS table) out of the this text file (through python or matlab will be preferable).

推荐答案

大多数情况下，您应该能够使用Astropy做到这一点.细节有些模糊，但是您应该能够将文本文件读入Astropy表中，例如:

You should be able to do this mostly with Astropy. The details are a little vague, but you should be able to read the text file into an Astropy table like:

>>> from astropy.table import Table
>>> table = Table.read('/path/to/text/file.txt', format='ascii')

最终传递给Table的选项可能在很大程度上取决于表的格式.

where the options you end up passing to Table might depend heavily on exactly how the table is formatted.

然后，您需要将列转换为Numpy数组.您的问题陈述有点含糊，但是如果表中的坐标只是像素坐标，则应该可以执行以下操作:

Then you need to convert the columns to a Numpy array. Your problem statement is a bit vague, but if the coordinates in your table are just pixel coordinates you should be able to do something like:

>>> import numpy as np
>>> img = np.zeros((len(table), len(table))
>>> for x, y, intensity in table:
...     img[x, y] = intensity

(我想知道Numpy是否有一种轻松的方式来做到这一点，但我不知道.)

(I have to wonder if Numpy has a slicker way of doing this but not that I know of.)

然后将图像保存到FITS文件:

Then to save the image to a FITS file:

>>> from astropy.io import fits
>>> fits.writeto('filename.fits', img)

这是一个非常高层次的过程.详细信息在很大程度上取决于您的数据.

That's the very high level process. The details depend a lot on your data.

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