Merge PR #371 (Bug fixes for stretched grid comparison plots)

This merge brings PR # (Bug fixes for stretched grid comparison plots,
by @lizziel) into the GCPy development stream.

PR #371 brings in the following changes to successfully compare
GCHP stretched grid against GCHP non-stretched grid in 6-panel
plots.

Signed-off-by: Bob Yantosca <yantosca@seas.harvard.edu>

Author: yantosca

CHANGELOG.md

@@ -16,10 +16,13 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Modified criteria for terminating read of log files in `benchmark_scrape_gcclassic_timers.py` to avoid being spoofed by  output that is attached by Intel VTune
 - Moved `gprofng_text_to_data_units` to function `text_to_data_units` in `gcpy/plot/core.py` so that it can be used by `gprofng_functions` and `vtune_plot_hotspots`
 - Updated GitHub badges in `README.md` and `docs/source/index.rst`
+- Expanded possible stretched grid attribute names to include STRETCH_FACTOR, TARGET_LAT, and TARGET_LON
+- Changed regridding for plots to always compare stretched-grid to uniform CS grid on the uniform CS grid rather than whatever grid is ref
 
 ### Fixed
-- Fix grid area calculation scripts of `grid_area` in `gcpy/gcpy/cstools.py`
+- Fixed grid area calculation scripts of `grid_area` in `gcpy/gcpy/cstools.py`
 - Fixed various security issues in GitHub Actions workflows
+- Fixed colorbar bounds for case of comparing cubed-sphere grids
 
 ## [1.6.2] - 2025-06-12
 ### Added

gcpy/plot/compare_single_level.py

@@ -253,17 +253,35 @@ def compare_single_level(
     # Get stretched-grid info if passed
     if sg_ref_path != '':
         sg_ref_attrs = xr.open_dataset(sg_ref_path).attrs
-        sg_ref_params = [
-            sg_ref_attrs['stretch_factor'],
-            sg_ref_attrs['target_longitude'],
-            sg_ref_attrs['target_latitude']]
+        if 'stretch_factor' in sg_ref_attrs:
+            sg_ref_params = [
+                sg_ref_attrs['stretch_factor'],
+                sg_ref_attrs['target_lon'],
+                sg_ref_attrs['target_lat']]
+        elif 'STRETCH_FACTOR' in sg_ref_attrs:
+            sg_ref_params = [
+                sg_ref_attrs['STRETCH_FACTOR'],
+                sg_ref_attrs['TARGET_LON'],
+                sg_ref_attrs['TARGET_LAT']]
+        else:
+            msg = "Stretched grid global parameters missing from ref file"
+            raise ValueError(msg)
 
     if sg_dev_path != '':
         sg_dev_attrs = xr.open_dataset(sg_dev_path).attrs
-        sg_dev_params = [
-            sg_dev_attrs['stretch_factor'],
-            sg_dev_attrs['target_longitude'],
-            sg_dev_attrs['target_latitude']]
+        if 'stretch_factor' in sg_dev_attrs:
+            sg_dev_params = [
+                sg_dev_attrs['stretch_factor'],
+                sg_dev_attrs['target_lon'],
+                sg_dev_attrs['target_lat']]
+        elif 'STRETCH_FACTOR' in sg_dev_attrs:
+            sg_dev_params = [
+                sg_dev_attrs['STRETCH_FACTOR'],
+                sg_dev_attrs['TARGET_LON'],
+                sg_dev_attrs['TARGET_LAT']]
+        else:
+            msg = "Stretched grid global parameters missing from dev file"
+            raise ValueError(msg)
 
     # Get grid info and regrid if necessary
     [refres, refgridtype, devres, devgridtype, cmpres, cmpgridtype, regridref,
@@ -505,14 +523,9 @@ def compare_single_level(
     for i in range(n_var):
         ds_refs[i] = reshape_MAPL_CS(ds_refs[i])
         ds_devs[i] = reshape_MAPL_CS(ds_devs[i])
-        #ds_ref_cmps[i] = reshape_MAPL_CS(ds_ref_cmps[i])
-        #ds_dev_cmps[i] = reshape_MAPL_CS(ds_dev_cmps[i])
         if diff_of_diffs:
             frac_ds_refs[i] = reshape_MAPL_CS(frac_ds_refs[i])
             frac_ds_devs[i] = reshape_MAPL_CS(frac_ds_devs[i])
-            #frac_ds_ref_cmps[i] = reshape_MAPL_CS(frac_ds_ref_cmps[i])
-            #frac_ds_dev_cmps[i] = reshape_MAPL_CS(frac_ds_dev_cmps[i])
-
 
     # ==================================================================
     # Create arrays for each variable in Ref and Dev datasets
@@ -696,7 +709,8 @@ def call_reshape(cmp_data):
             frac_ds_dev_cmp_reshaped = call_reshape(frac_ds_dev_cmp)
 
         # ==============================================================
-        # Get min and max values for use in the colorbars
+        # Get min and max values for use in the top-row plot colorbars
+        # and also flag if Ref and/or Dev are all zero or all NaN.
         # ==============================================================
 
         # Choose from values within plot extent
@@ -753,31 +767,25 @@ def get_extent_for_colors(dset, minlon, maxlon, minlat, maxlat):
             min_max_maxlat
         )
 
-        # Ref
-        vmin_ref = float(np.nanmin(ds_ref_reg.data))
-        vmax_ref = float(np.nanmax(ds_ref_reg.data))
+        # Use global data to determine cbar bounds if plotting cubed-sphere
+        if refgridtype == "cs":
+            vmin_ref = float(np.nanmin(ds_ref.data))
+            vmax_ref = float(np.nanmax(ds_ref.data))
+        else:
+            vmin_ref = float(np.nanmin(ds_ref_reg.data))
+            vmax_ref = float(np.nanmax(ds_ref_reg.data))
+
+        if devgridtype == "cs":
+            vmin_dev = float(np.nanmin(ds_dev.data))
+            vmax_dev = float(np.nanmax(ds_dev.data))
+        else:
+            vmin_dev = float(np.nanmin(ds_dev_reg.data))
+            vmax_dev = float(np.nanmax(ds_dev_reg.data))
+
+        # Set vmin_both and vmax_both to use if match_cbar=True
+        vmin_both = np.nanmin([vmin_ref, vmin_dev])
+        vmax_both = np.nanmax([vmax_ref, vmax_dev])
 
-        # Dev
-        vmin_dev = float(np.nanmin(ds_dev_reg.data))
-        vmax_dev = float(np.nanmax(ds_dev_reg.data))
-
-# Pylint says that these are unused variables, so comment out
-#  -- Bob Yantosca (15 Aug 2023)
-#        # Comparison
-#        if cmpgridtype == "cs":
-#            vmin_ref_cmp = float(np.nanmin(ds_ref_cmp))
-#            vmax_ref_cmp = float(np.nanmax(ds_ref_cmp))
-#            vmin_dev_cmp = float(np.nanmin(ds_dev_cmp))
-#            vmax_dev_cmp = float(np.nanmax(ds_dev_cmp))
-#            vmin_cmp = np.nanmin([vmin_ref_cmp, vmin_dev_cmp])
-#            vmax_cmp = np.nanmax([vmax_ref_cmp, vmax_dev_cmp])
-#        else:
-#            vmin_cmp = np.nanmin([np.nanmin(ds_ref_cmp), np.nanmin(ds_dev_cmp)])
-#            vmax_cmp = np.nanmax([np.nanmax(ds_ref_cmp), np.nanmax(ds_dev_cmp)])
-
-        # Get overall min & max
-        vmin_abs = np.nanmin([vmin_ref, vmin_dev])#, vmin_cmp])
-        vmax_abs = np.nanmax([vmax_ref, vmax_dev])#, vmax_cmp])
         # ==============================================================
         # Test if Ref and/or Dev contain all zeroes or all NaNs.
         # This will have implications as to how we set min and max
@@ -1064,8 +1072,8 @@ def get_extent_for_colors(dset, minlon, maxlon, minlat, maxlat):
         other_all_nans = [dev_is_all_nan, ref_is_all_nan,
                           False, False, False, False]
 
-        mins = [vmin_ref, vmin_dev, vmin_abs]
-        maxs = [vmax_ref, vmax_dev, vmax_abs]
+        mins = [vmin_ref, vmin_dev, vmin_both]
+        maxs = [vmax_ref, vmax_dev, vmax_both]
 
         ratio_logs = [False, False, False, False, True, True]
 

gcpy/plot/compare_zonal_mean.py

@@ -316,17 +316,35 @@ def compare_zonal_mean(
     # Get stretched-grid info if passed
     if sg_ref_path != '':
         sg_ref_attrs = xr.open_dataset(sg_ref_path).attrs
-        sg_ref_params = [
-            sg_ref_attrs['stretch_factor'],
-            sg_ref_attrs['target_longitude'],
-            sg_ref_attrs['target_latitude']]
+        if 'stretch_factor' in sg_ref_attrs:
+            sg_ref_params = [
+                sg_ref_attrs['stretch_factor'],
+                sg_ref_attrs['target_lon'],
+                sg_ref_attrs['target_lat']]
+        elif 'STRETCH_FACTOR' in sg_ref_attrs:
+            sg_ref_params = [
+                sg_ref_attrs['STRETCH_FACTOR'],
+                sg_ref_attrs['TARGET_LON'],
+                sg_ref_attrs['TARGET_LAT']]
+        else:
+            msg = "Stretched grid global parameters missing from ref file"
+            raise ValueError(msg)
 
     if sg_dev_path != '':
         sg_dev_attrs = xr.open_dataset(sg_dev_path).attrs
-        sg_dev_params = [
-            sg_dev_attrs['stretch_factor'],
-            sg_dev_attrs['target_longitude'],
-            sg_dev_attrs['target_latitude']]
+        if 'stretch_factor' in sg_dev_attrs:
+            sg_dev_params = [
+                sg_dev_attrs['stretch_factor'],
+                sg_dev_attrs['target_lon'],
+                sg_dev_attrs['target_lat']]
+        elif 'STRETCH_FACTOR' in sg_dev_attrs:
+            sg_dev_params = [
+                sg_dev_attrs['STRETCH_FACTOR'],
+                sg_dev_attrs['TARGET_LON'],
+                sg_dev_attrs['TARGET_LAT']]
+        else:
+            msg = "Stretched grid global parameters missing from dev file"
+            raise ValueError(msg)
 
     [refres, refgridtype, devres, devgridtype, cmpres, cmpgridtype,
      regridref, regriddev, regridany, refgrid, devgrid, cmpgrid,
@@ -723,15 +741,17 @@ def createfig(ivar, temp_dir=''):
             zm_dev = ds_dev.mean(dim="lon")
         else:
             zm_dev = ds_dev.mean(axis=2)
+
         # Comparison
         zm_dev_cmp = ds_dev_cmp.mean(axis=2)
         zm_ref_cmp = ds_ref_cmp.mean(axis=2)
         if diff_of_diffs:
             frac_zm_dev_cmp = frac_ds_dev_cmp.mean(axis=2)
             frac_zm_ref_cmp = frac_ds_ref_cmp.mean(axis=2)
+
         # ==============================================================
-        # Get min and max values for use in the colorbars
-        # and also flag if Ref and/or Dev are all zero or all NaN
+        # Get min and max values for use in the top-row plot colorbars
+        # and also flag if Ref and/or Dev are all zero or all NaN.
         # ==============================================================
 
         # Ref
@@ -742,13 +762,9 @@ def createfig(ivar, temp_dir=''):
         vmin_dev = float(zm_dev.min())
         vmax_dev = float(zm_dev.max())
 
-        # Comparison
-        vmin_cmp = np.min([zm_ref_cmp.min(), zm_dev_cmp.min()])
-        vmax_cmp = np.max([zm_ref_cmp.max(), zm_dev_cmp.max()])
-
-        # Take min/max across all grids
-        vmin_abs = np.min([vmin_ref, vmin_dev, vmin_cmp])
-        vmax_abs = np.max([vmax_ref, vmax_dev, vmax_cmp])
+        # Set vmin_both and vmax_both to use if match_cbar=True
+        vmin_both = np.min([vmin_ref, vmin_dev])
+        vmax_both = np.max([vmax_ref, vmax_dev])
 
         # ==============================================================
         # Test if Ref and/or Dev contain all zeroes or all NaNs.
@@ -955,8 +971,8 @@ def createfig(ivar, temp_dir=''):
         pedge_inds = [ref_pedge_ind, dev_pedge_ind, pedge_ind,
                       pedge_ind, pedge_ind, pedge_ind]
 
-        mins = [vmin_ref, vmin_dev, vmin_abs]
-        maxs = [vmax_ref, vmax_dev, vmax_abs]
+        mins = [vmin_ref, vmin_dev, vmin_both]
+        maxs = [vmax_ref, vmax_dev, vmax_both]
 
         ratio_logs = [False, False, False, False, True, True]
         # Plot

gcpy/plot/six_plot.py

@@ -103,10 +103,10 @@ def six_plot(
         "ll" for lat/lon or "cs" for cubed-sphere.
     vmins: list of float
         list of length 3 of minimum ref value, dev value,
-        and absdiff value.
+        and minimum of both (for use with match_cbar=True).
     vmaxs: list of float
         list of length 3 of maximum ref value, dev value,
-        and absdiff value.
+        and maximum of both (for use with match_cbar=True)
     use_cmap_RdBu: bool
         Set this flag to True to use a blue-white-red colormap
     match_cbar: bool
@@ -425,7 +425,7 @@ def vmin_vmax_for_ref_dev_plots(
     #---------------------------------------------------------------
     if use_cmap_RdBu:
 
-        # Ref supblot, diff-of-diffs
+        # Ref subplot, diff-of-diffs
         if subplot in "ref":
             vmax = max([np.abs(vmins[0]), np.abs(vmaxs[0])])
             if match_cbar and not other_all_nan:

gcpy/regrid.py

@@ -431,12 +431,16 @@ def create_regridders(
                     "Warning: zonal mean comparison must be lat-lon. Defaulting to 1x1.25")
                 cmpres = '1x1.25'
                 cmpgridtype = "ll"
-            elif sg_ref_params != [1, 170, -90] or sg_dev_params != [1, 170, -90]:
-                # pick ref grid when a stretched-grid and non-stretched-grid
-                # are passed
+            elif sg_ref_params == [1, 170, -90] and sg_dev_params != [1, 170, -90]:
+                # pick ref grid if dev is stretched and ref is not
                 cmpres = refres
                 cmpgridtype = "cs"
                 sg_cmp_params = sg_ref_params
+            elif sg_ref_params != [1, 170, -90] and sg_dev_params == [1, 170, -90]:
+                # pick dev grid if ref is stretched and dev is not
+                cmpres = devres
+                cmpgridtype = "cs"
+                sg_cmp_params = sg_dev_params
             else:
                 # pick higher resolution CS grid out of two standard
                 # cubed-sphere grids