https://github.com/esheldon/smatch

Code to match points on the sphere using the healpix scheme
https://github.com/esheldon/smatch

Last synced: 11 days ago
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Code to match points on the sphere using the healpix scheme

• Host: GitHub
• URL: https://github.com/esheldon/smatch
• Owner: esheldon
• License: other
• Created: 2012-02-07T18:37:45.000Z (over 12 years ago)
• Default Branch: master
• Last Pushed: 2024-01-10T18:27:14.000Z (10 months ago)
• Last Synced: 2024-10-11T19:25:51.958Z (27 days ago)
• Language: C
• Homepage:
• Size: 331 KB
• Stars: 12
• Watchers: 5
• Forks: 3
• Open Issues: 3
• Metadata Files:
  • Readme: README.md
  • License: LICENSE

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README

        
A python code for matching points on the sphere using healpix.

This code is about 5-10 times faster than HTM in the esutil library.

Examples

--------

```python

# For quick matches, use the match() function

import smatch

# This code uses the ring configuration. This means nside can be any  positive

# integer between 1 and 2**28=268435456, although beware the memory usage grows

# with nside

nside=4096 # healpix nside

maxmatch=1 # return closest match

# ra,dec,radius in degrees

matches = smatch.match(ra1, dec2, radius, ra2, dec2,

                       nside=nside, maxmatch=maxmatch)

# in the above call, radius can be a scalar or the

# same size as ra1,dec1

# the output matches structure holds the indices of the matches from each data

# set, and the cosine of the distance between them

print(m.dtype.descr)

    [('i1', '