Fixes for spacetelescope/gwcs#545

Author: Cadair

docs/explaining_ndcube/tabular_coordinates.rst

@@ -54,7 +54,7 @@ is the following temporal axis::
 
   >>> gwcs = TimeTableCoordinate(time_axis).wcs
   >>> gwcs
-  <WCS(output_frame=TemporalFrame, input_frame=PixelFrame, forward_transform=Model: Tabular1D
+  <WCS(output_frame=TemporalFrame, input_frame=Frame..., forward_transform=Model: Tabular1D
   N_inputs: 1
   N_outputs: 1
   Parameters:
@@ -86,7 +86,7 @@ This keyword argument interprets the input to `.SkyCoordTableCoordinate` in a si
 
   >>> gwcs = (TimeTableCoordinate(time_axis) & SkyCoordTableCoordinate(icrs_table, mesh=True)).wcs
   >>> gwcs
-  <WCS(output_frame=CompositeFrame, input_frame=PixelFrame, forward_transform=Model: CompoundModel
+  <WCS(output_frame=CompositeFrame, input_frame=Frame..., forward_transform=Model: CompoundModel
   Inputs: ('x', 'x0', 'x1')
   Outputs: ('y', 'y0', 'y1')
   Model set size: 1

ndcube/extra_coords/table_coord.py

@@ -1,5 +1,6 @@
 import abc
 import copy
+import uuid
 from numbers import Integral
 from functools import partial
 from collections import defaultdict
@@ -111,7 +112,12 @@ def _generate_generic_frame(naxes, unit, names=None, physical_types=None):
     """
     axes_order = tuple(range(naxes))
 
-    name = None
+    if names is None:
+        # Ensure that the frame name is always unique
+        name = f"Frame-{str(uuid.uuid4()).split('-')[1]}"
+    else:
+        # If we have axes names use them as the frame name
+        name = "-".join(names) + " Frame"
     axes_type = "CUSTOM"
 
     if isinstance(unit, (u.Unit, u.IrreducibleUnit, u.CompositeUnit)):
@@ -121,7 +127,6 @@ def _generate_generic_frame(naxes, unit, names=None, physical_types=None):
         axes_type = "SPATIAL"
 
     if all(u.pix.is_equivalent(un) for un in unit):
-        name = "PixelFrame"
         axes_type = "PIXEL"
 
     axes_type = tuple([axes_type] * naxes)