WCS.jl

Astronomical World Coordinate System library for Julia. This package wraps the WCSLIB C library.

Example

julia> using WCS

# create a transformation from scratch
julia> wcs = WCSTransform(2;
           cdelt = [-0.066667, 0.066667],
           ctype = ["RA---AIR", "DEC--AIR"],
           crpix = [-234.75, 8.3393],
           crval = [0., -90],
           pv    = [(2, 1, 45.0)],
       )
WCSTransform(naxis=2)

# ... or from a FITS header
julia> wcs_array = WCS.from_header(header)

julia> wcs = wcs_array[1]


# convert pixel -> world coordinates
julia> pixcoords = [0.0  24.0  45.0;  # x coordinates
                    0.0  38.0  98.0]  # y coordinates

julia> worldcoords = pix_to_world(wcs, pixcoords)
2x3 Array{Float64,2}:
 267.965   276.539   287.771 
 -73.7366  -71.9741  -69.6781


# convert world -> pixel coordinates
julia> pixcoords = world_to_pix(wcs, worldcoords)
2x3 Array{Float64,2}:
  1.16529e-12  24.0  45.0
 -7.10543e-14  38.0  98.0


# convert a WCSTransform to a FITS header
header = WCS.to_header(wcs)

# check what underlying C library version is being used.
julia> WCS.wcslib_version()
v"6.2.0"

Development documentation

Tests

Tests are run with ParallelTestRunner.jl, which hooks into the standard Pkg.test harness for more granular control. See below for some brief usage examples run from the package root directory:

julia --proj

julia> using Pkg

List available testsets:

julia> Pkg.test("WCS"; test_args = `--list`)

Run all tests

pkg> test

Run specific tests

julia> Pkg.test("WCS"; test_args = `--verbose <testset name>`, julia_args = `--threads=auto`)

Documentation

Add LiveServer.jl to your global env and then run the following from the package root directory:

julia --proj=docs/

julia> using LiveServer

julia> servedocs()

License

The Julia code in this repository is distributed under the MIT license. Note that WCS.jl wraps the WCSLIB C library, which is released under the LGPL license.