6 ms·

Python-Based Tools for the Space Science Community

76 points by neokya 13y ago

dfc 13y ago
I cant think of another discipline where the first example from the time section will use a Julian Day: >>> x=Ticktock([2452331.0142361112, 2452332.0142361112], 'JD')
gshubert17 13y ago
The documentation mentions that "OSX install has become a challenge. With the Enthought transition to Canopy we cannot figure out clean install directions for 3rd party packages and therefore can no longer recommend using EPD for SpacePy." They have other directions including some using MacPorts. Installation directions for Linux and Windows seem straight-forward.
- leephillips 13y ago
  This is a familiar story for this type of software. It has consistently been my experience that installation on OSX is likely to be a headache, whereas on linux it's effortless. Never tried Windows.
- Fomite 13y ago
  Enthought going to Canopy as some weird hybrid of a distribution, and IDE and a package manager may have something to do with it. I'm had many fewer issues with Anaconda, and have found that OS X behaves just as well as Scientific Linux or Mint for stuff like this.
neokya 13y ago
Can anyone clarify what does this means: 'License Agreement based on Python Software Foundation License'?
- maaku 13y ago
  http://lmgtfy.com/?q=Python+Software+Foundation+License http://lmgtfy.com/?q=Python+Software+Foundation+License
  - neokya 13y ago
    haha, thanks ;)
mtct 13y ago
Fortunately Python is becoming the new programming language for science and engineering, replacing FORTRAN and Matlab. Unfortunately I do not see many opportunities for growth in other sectors
- leephillips 13y ago
  This is only partly true, and in a limited way. Fortran is still king for simulations or anything that needs to be fast. Other possibilities are C and assembler, and that's about it. Python + numpy has become very popular very fast for exploring data and the results of simulations, and it's a great environment for this. Note that when you use numpy you're calling fortran (and C?) routines. The fortran languages and compilers continue to evolve, and fortran will probably remain the language of choice for large-scale computation for some time. Other languages, such as Java and lisps, are sometimes used for big simulations, but Python is just too slow to be used for anything but prototyping.
  - yummyfajitas 13y ago
    This depends very strongly on the nature of the simulation. Lots of simulations are handled just perfectly by modelling your system as arrays. Consider, for example, nonlinear waves. Your simulation typically consists of FFT -> k-domain operator -> IFFT -> x-domain operator (repeat for i=0...T/dt). No reason whatsoever not to do this in python, though of course the FFT is just fftw/fftpack and the x/k domain operators are numpy ufuncs (all written in C/Fortran). On the other hand, for particle simulations, you need more complicated logic/data structures to handle multipole methods, so the python array model might not work so well.
    - leephillips 13y ago
      Yes, it seems that there are some types of simulations that could be structured as numpy operations steered by a little Python code. But can this kind of code be run effectively on large multi-processor machines?
      - 13y ago
celias 13y ago
This is one of the few (only?) python packages that can read and write files in NASA's CDF format - http://cdf.gsfc.nasa.gov http://cdf.gsfc.nasa.gov Installing under OS X is fairly straightforward following the directions in the documentation.
siddboots 13y ago
Somewhat related, I just discovered PyEphem, and have been using it to pin down a time and location from the stars that appear in XKCD #1190 http://forums.xkcd.com/viewtopic.php?f=7&t=101043&p=3395021#p3394991 http://forums.xkcd.com/viewtopic.php?f=7&t=101043&p=3395021#... http://rhodesmill.org/pyephem/ http://rhodesmill.org/pyephem/
- maxerickson 13y ago
  I wonder if Randall Munroe also used it to calculate the positions of those stars? He has mentioned it in some other places. (I did not wade into that 970 page thread to see if someone had already made a similar suggestion)
  - siddboots 13y ago
    If you save down one of the images and up the gamma a little, you can see a tremendous amount of detail. Far more than could practically be done by hand, and afaict, more than PyEphem has in its catalogue of "bright stars". I suspect he used something like Stellarium and then ran the images though some filters.
pwang 13y ago
"OSX install has become a challenge. With the Enthought transition to Canopy we cannot figure out clean install directions for 3rd party packages and therefore can no longer recommend using EPD for SpacePy." Um... use Anaconda? http://continuum.io/anaconda http://continuum.io/anaconda
- westurner 13y ago
  The Python installation tool utilized to install different versions of Anaconda and component packages is called [conda](http://docs.continuum.io/conda/intro.html http://docs.continuum.io/conda/intro.html). [pythonbrew]( https://github.com/utahta/pythonbrew https://github.com/utahta/pythonbrew) in combination with [virtualenvwrapper](http://virtualenvwrapper.readthedocs.org/en/latest/ http://virtualenvwrapper.readthedocs.org/en/latest/) is also great.

76 points by neokya 13y ago

dfc 13y ago

I cant think of another discipline where the first example from the time section will use a Julian Day: >>> x=Ticktock([2452331.0142361112, 2452332.0142361112], 'JD')

gshubert17 13y ago

The documentation mentions that "OSX install has become a challenge. With the Enthought transition to Canopy we cannot figure out clean install directions for 3rd party packages and therefore can no longer recommend using EPD for SpacePy." They have other directions including some using MacPorts. Installation directions for Linux and Windows seem straight-forward.

leephillips 13y ago
This is a familiar story for this type of software. It has consistently been my experience that installation on OSX is likely to be a headache, whereas on linux it's effortless. Never tried Windows.
Fomite 13y ago
Enthought going to Canopy as some weird hybrid of a distribution, and IDE and a package manager may have something to do with it. I'm had many fewer issues with Anaconda, and have found that OS X behaves just as well as Scientific Linux or Mint for stuff like this.

neokya 13y ago

Can anyone clarify what does this means: 'License Agreement based on Python Software Foundation License'?

maaku 13y ago
http://lmgtfy.com/?q=Python+Software+Foundation+License http://lmgtfy.com/?q=Python+Software+Foundation+License
- neokya 13y ago
  haha, thanks ;)

mtct 13y ago

Fortunately Python is becoming the new programming language for science and engineering, replacing FORTRAN and Matlab. Unfortunately I do not see many opportunities for growth in other sectors

leephillips 13y ago
This is only partly true, and in a limited way. Fortran is still king for simulations or anything that needs to be fast. Other possibilities are C and assembler, and that's about it. Python + numpy has become very popular very fast for exploring data and the results of simulations, and it's a great environment for this. Note that when you use numpy you're calling fortran (and C?) routines. The fortran languages and compilers continue to evolve, and fortran will probably remain the language of choice for large-scale computation for some time. Other languages, such as Java and lisps, are sometimes used for big simulations, but Python is just too slow to be used for anything but prototyping.
- yummyfajitas 13y ago
  This depends very strongly on the nature of the simulation. Lots of simulations are handled just perfectly by modelling your system as arrays. Consider, for example, nonlinear waves. Your simulation typically consists of FFT -> k-domain operator -> IFFT -> x-domain operator (repeat for i=0...T/dt). No reason whatsoever not to do this in python, though of course the FFT is just fftw/fftpack and the x/k domain operators are numpy ufuncs (all written in C/Fortran). On the other hand, for particle simulations, you need more complicated logic/data structures to handle multipole methods, so the python array model might not work so well.
  - leephillips 13y ago
    Yes, it seems that there are some types of simulations that could be structured as numpy operations steered by a little Python code. But can this kind of code be run effectively on large multi-processor machines?
    - 13y ago

celias 13y ago

This is one of the few (only?) python packages that can read and write files in NASA's CDF format - http://cdf.gsfc.nasa.gov http://cdf.gsfc.nasa.gov Installing under OS X is fairly straightforward following the directions in the documentation.

siddboots 13y ago

Somewhat related, I just discovered PyEphem, and have been using it to pin down a time and location from the stars that appear in XKCD #1190 http://forums.xkcd.com/viewtopic.php?f=7&t=101043&p=3395021#p3394991 http://forums.xkcd.com/viewtopic.php?f=7&t=101043&p=3395021#... http://rhodesmill.org/pyephem/ http://rhodesmill.org/pyephem/

maxerickson 13y ago
I wonder if Randall Munroe also used it to calculate the positions of those stars? He has mentioned it in some other places. (I did not wade into that 970 page thread to see if someone had already made a similar suggestion)
- siddboots 13y ago
  If you save down one of the images and up the gamma a little, you can see a tremendous amount of detail. Far more than could practically be done by hand, and afaict, more than PyEphem has in its catalogue of "bright stars". I suspect he used something like Stellarium and then ran the images though some filters.

pwang 13y ago

"OSX install has become a challenge. With the Enthought transition to Canopy we cannot figure out clean install directions for 3rd party packages and therefore can no longer recommend using EPD for SpacePy." Um... use Anaconda? http://continuum.io/anaconda http://continuum.io/anaconda

westurner 13y ago
The Python installation tool utilized to install different versions of Anaconda and component packages is called [conda](http://docs.continuum.io/conda/intro.html http://docs.continuum.io/conda/intro.html). [pythonbrew]( https://github.com/utahta/pythonbrew https://github.com/utahta/pythonbrew) in combination with [virtualenvwrapper](http://virtualenvwrapper.readthedocs.org/en/latest/ http://virtualenvwrapper.readthedocs.org/en/latest/) is also great.