Fix spline interpolation between different unit physical types (astro…

…py#1190) * Use edges in new unit for comparison * Fix changelog * Add test
rosteen · Nov 5, 2024 · 4bcf381 · 4bcf381
1 parent 36afc8a
commit 4bcf381
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Showing 3 changed files with 21 additions and 3 deletions.
diff --git a/CHANGES.rst b/CHANGES.rst
@@ -12,6 +12,9 @@ Bug Fixes
 
 - Fixed automatic format detection for SDSS-V ``SpectrumList`` default loaders. [#1185]
 
+- Fixed ``SplineInterpolatedResampler`` when input and output spectral axes are different
+  physical types, e.g. wavelength and velocity. [#1190]
+
 Other Changes and Additions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
@@ -35,7 +38,6 @@ Bug Fixes
 - Fixed extracting a spectral region when one of spectrum/region is in wavelength
   and the other is in frequency units. [#1187]
 
-
 Other Changes and Additions
 ^^^^^^^^^^^^^^^^^^^^^^^^^^^
 

diff --git a/specutils/manipulation/resample.py b/specutils/manipulation/resample.py
@@ -461,7 +461,7 @@ def resample1d(self, orig_spectrum, fin_spec_axis):
         if self.extrapolation_treatment == 'zero_fill':
             fill_val = 0
 
-        orig_edges = orig_spectrum.spectral_axis.bin_edges
+        orig_edges = orig_axis_in_new.bin_edges
         off_edges = (fin_spec_axis < np.min(orig_edges)) | (np.max(orig_edges) < fin_spec_axis)
         out_flux_val[off_edges] = fill_val
         if new_unc is not None:

diff --git a/specutils/tests/test_resample.py b/specutils/tests/test_resample.py
@@ -4,7 +4,7 @@
 from astropy.nddata import VarianceUncertainty, InverseVariance, StdDevUncertainty
 from astropy.tests.helper import assert_quantity_allclose
 
-from ..spectra.spectrum1d import Spectrum1D
+from ..spectra.spectrum1d import Spectrum1D, SpectralAxis
 from ..manipulation.resample import FluxConservingResampler, LinearInterpolatedResampler, SplineInterpolatedResampler
 
 
@@ -214,6 +214,22 @@ def test_resample_different_units(all_resamplers):
     resampled = resampler(input_spectrum, resamp_grid)
     assert not np.any(np.isnan(resampled.flux))
 
+    resamp_grid = [550, 650]*u.nm
+    resampled = resampler(input_spectrum, resamp_grid)
+
+    # Test conversion to velocity grid
+    rest_wavelength = 656.2 * u.nm
+    wavelengths = np.linspace(640, 672, 10) * u.nm
+    flux = np.ones(10) * u.mJy
+    spec1d = Spectrum1D(spectral_axis=wavelengths, velocity_convention="optical", flux=flux)
+    spec1d.spectral_axis.doppler_rest = rest_wavelength
+
+    velocities = np.linspace(-1000, 1000, 5) * u.km/u.s
+    velocity_grid = SpectralAxis(velocities, doppler_rest=rest_wavelength,
+                                 doppler_convention="optical")
+    velocity_binned = resampler(spec1d, velocity_grid)
+    assert not np.any(np.isnan(velocity_binned.flux))
+
 
 def test_resample_uncs(all_resamplers):
     sdunc = StdDevUncertainty([0.1, 0.2, 0.3]*u.mJy)