add support for scientific notation in unit string (#3200)

* add support for scientific notation in unit string, update associated tests

* update test to use scaled values

* add changes.rst

CHANGES.rst

@@ -6,7 +6,7 @@ New Features
 
 - Added flux/surface brightness translation and surface brightness
   unit conversion in Cubeviz and Specviz. [#2781, #2940, #3088, #3111, #3113, #3129,
-  #3139, #3149, #3155, #3178, #3185, #3187, #3190, #3156]
+  #3139, #3149, #3155, #3178, #3185, #3187, #3190, #3156, #3200]
 
 - Plugin tray is now open by default. [#2892]
 

jdaviz/configs/cubeviz/plugins/parsers.py

@@ -178,7 +178,7 @@ def _get_celestial_wcs(wcs):
     return wcs.celestial if hasattr(wcs, 'celestial') else None
 
 
-def _return_spectrum_with_correct_units(flux, wcs, metadata, data_type,
+def _return_spectrum_with_correct_units(flux, wcs, metadata, data_type=None,
                                         target_wave_unit=None, hdulist=None,
                                         uncertainty=None, mask=None, apply_pix2=False):
     """Upstream issue of WCS not using the correct units for data must be fixed here.
@@ -199,6 +199,10 @@ def _return_spectrum_with_correct_units(flux, wcs, metadata, data_type,
                 if uncertainty is not None:
                     uncertainty = uncertainty / (u.pix * u.pix)
 
+        # handle scale factors when they are included in the unit
+        if not np.isclose(flux.unit.scale, 1.0, rtol=1e-5):
+            flux = flux.to(flux.unit / flux.unit.scale)
+
         sc = Spectrum1D(flux=flux, wcs=wcs, uncertainty=uncertainty, mask=mask)
 
     if target_wave_unit is None and hdulist is not None:
@@ -461,7 +465,7 @@ def _parse_spectrum1d_3d(app, file_obj, data_label=None,
             if hasattr(file_obj, 'wcs'):
                 meta['_orig_spatial_wcs'] = _get_celestial_wcs(file_obj.wcs)
 
-            s1d = Spectrum1D(flux=flux, wcs=file_obj.wcs, meta=meta)
+            s1d = _return_spectrum_with_correct_units(flux, wcs=file_obj.wcs, metadata=meta)
 
             # convert data loaded in flux units to a per-square-pixel surface
             # brightness unit (e.g Jy to Jy/pix**2)

jdaviz/configs/cubeviz/plugins/spectral_extraction/tests/test_spectral_extraction.py

@@ -432,12 +432,12 @@ def test_cube_extraction_with_nan(cubeviz_helper, image_cube_hdu_obj):
     cubeviz_helper.load_data(image_cube_hdu_obj, data_label="with_nan")
     extract_plg = cubeviz_helper.plugins['Spectral Extraction']
     sp = extract_plg.extract()  # Default settings (sum)
-    assert_allclose(sp.flux.value, 96)  # (10 x 10) - 4
+    assert_allclose(sp.flux.value, 9.6E-16)  # (10 x 10) - 4
 
     cubeviz_helper.load_regions(RectanglePixelRegion(PixCoord(1.5, 1.5), width=4, height=4))
     extract_plg.aperture = 'Subset 1'
     sp_subset = extract_plg.extract()  # Default settings but on Subset
-    assert_allclose(sp_subset.flux.value, 12)  # (4 x 4) - 4
+    assert_allclose(sp_subset.flux.value, 1.2E-16)  # (4 x 4) - 4
 
 
 def test_autoupdate_results(cubeviz_helper, spectrum1d_cube_largest):

jdaviz/configs/cubeviz/plugins/tests/test_parsers.py

@@ -45,10 +45,17 @@ def test_fits_image_hdu_with_microns(image_cube_hdu_obj_microns, cubeviz_helper)
     label_mouseover = cubeviz_helper.app.session.application._tools['g-coords-info']
     label_mouseover._viewer_mouse_event(flux_viewer,
                                         {'event': 'mousemove', 'domain': {'x': 0, 'y': 0}})
+
+    # This secondarily tests a scale factor embedded in a unit at parse-time to make sure it
+    # is applied to the values, then it is removed from the actual display unit
     flux_unit_str = "erg / (Angstrom s cm2 pix2)"
-    assert label_mouseover.as_text() == (f'Pixel x=00.0 y=00.0 Value +5.00000e+00 1e-17 {flux_unit_str}',  # noqa
+    assert label_mouseover.as_text() == (f'Pixel x=00.0 y=00.0 Value +5.00000e-17 {flux_unit_str}',  # noqa
                                          'World 13h41m45.5759s +27d00m12.3044s (ICRS)',
                                          '205.4398995981 27.0034178810 (deg)')  # noqa
+
+    # verify that scale factor embedded in unit is removed
+    assert np.allclose(flux_cube.unit.scale, 1.0)
+
     unc_viewer = cubeviz_helper.app.get_viewer('uncert-viewer')
     label_mouseover._viewer_mouse_event(unc_viewer,
                                         {'event': 'mousemove', 'domain': {'x': -1, 'y': 0}})
@@ -87,7 +94,6 @@ def test_fits_image_hdu_parse_from_file(tmpdir, image_cube_hdu_obj, cubeviz_help
     assert cubeviz_helper.app.data_collection[0].label == "test_fits_image.fits[FLUX]"
 
     # This tests the same data as test_fits_image_hdu_parse above.
-
     cubeviz_helper.app.data_collection[0].meta['EXTNAME'] == 'FLUX'
     cubeviz_helper.app.data_collection[1].meta['EXTNAME'] == 'MASK'
     cubeviz_helper.app.data_collection[2].meta['EXTNAME'] == 'ERR'
@@ -99,7 +105,7 @@ def test_fits_image_hdu_parse_from_file(tmpdir, image_cube_hdu_obj, cubeviz_help
     label_mouseover._viewer_mouse_event(flux_viewer,
                                         {'event': 'mousemove', 'domain': {'x': 0, 'y': 0}})
     flux_unit_str = "erg / (Angstrom s cm2 pix2)"
-    assert label_mouseover.as_text() == (f'Pixel x=00.0 y=00.0 Value +1.00000e+00 1e-17 {flux_unit_str}',  # noqa
+    assert label_mouseover.as_text() == (f'Pixel x=00.0 y=00.0 Value +1.00000e-17 {flux_unit_str}',  # noqa
                                          'World 13h41m46.5994s +26d59m58.6136s (ICRS)',
                                          '205.4441642302 26.9996148973 (deg)')
 
@@ -129,12 +135,11 @@ def test_spectrum3d_parse(image_cube_hdu_obj, cubeviz_helper):
     label_mouseover._viewer_mouse_event(flux_viewer,
                                         {'event': 'mousemove', 'domain': {'x': 0, 'y': 0}})
     flux_unit_str = "erg / (Angstrom s cm2 pix2)"
-    assert label_mouseover.as_text() == (f'Pixel x=00.0 y=00.0 Value +1.00000e+00 1e-17 {flux_unit_str}',  # noqa
+    assert label_mouseover.as_text() == (f'Pixel x=00.0 y=00.0 Value +1.00000e-17 {flux_unit_str}',  # noqa
                                          'World 13h41m46.5994s +26d59m58.6136s (ICRS)',
                                          '205.4441642302 26.9996148973 (deg)')
 
     # These viewers have no data.
-
     unc_viewer = cubeviz_helper.app.get_viewer(cubeviz_helper._default_uncert_viewer_reference_name)
     label_mouseover._viewer_mouse_event(unc_viewer,
                                         {'event': 'mousemove', 'domain': {'x': -1, 'y': 0}})