FIX: Fix unnecessary coordinate reduction for SCRIP in chunked-rwg #497

- Also added some more example scripts
- Moved CTSM examples into own directory

examples/CTSM-MapData-Workflow/convert_to_shapefile.py

@@ -0,0 +1,24 @@
+import ocgis
+
+# Path to the file of interest
+PATH = "/home/benkoziol/Dropbox/dtmp/ctsm-grids/SCRIPgrid_4x5_nomask_c110308.nc"
+# The metadata/IO driver for the data file.
+DRIVER="netcdf-scrip"
+
+# ----------------------------------------------------------------------------------------------------------------------
+
+# The request dataset provides metadata for a field.
+rd = ocgis.RequestDataset(PATH, driver=DRIVER)
+# The field is similar to ESMF Field and provides access to grids, etc. It can also hold multiple data variables.
+field = rd.create_field()
+# Convert the coordinates into Shapely polygon objects.
+print("This is the geometry abstraction that will be used: {}".format(field.grid.abstraction))
+field.set_abstraction_geom()
+print("Sending polygons to a shapefile...")
+field.geom.write_vector("/tmp/shp_polygon.shp")
+
+# Can also write the points in another way...
+field.grid.abstraction = "point"
+points = field.grid.get_abstraction_geometry()
+points.write_vector("/tmp/shp_points.shp")
+

examples/CTSM-MapData-Workflow/do-chunked-rwg-ctsm-scrip.sh

@@ -0,0 +1,42 @@
+#!/usr/bin/env bash
+
+# The base or working directory.
+WD=~/scratch/
+
+# Directory to write all the chunked files to.
+CHUNKDIR=${WD}/chunking
+
+# Path to the source field/grid netCDF file.
+SRC="/home/ubuntu/Dropbox/dtmp/ctsm-grids/SCRIPgrid_0.5x0.5_AVHRR_c110228.nc"
+SRCTYPE="SCRIP"
+SRC_MAXSPATIALRES=0.5
+
+# Path to the destination field/grid netCDF file.
+DST="/home/ubuntu/Dropbox/dtmp/ctsm-grids/SCRIPgrid_4x5_nomask_c110308.nc"
+DSTTYPE="SCRIP"
+DST_MAXSPATIALRES=0.5
+
+# Chunking composition for the destination grid (n_chunks_y,n_chunks_x).
+NCHUNKS_DST=10
+
+# Path to the merged output weight file.
+WEIGHTS=${WD}/weights.nc
+
+# The ocli python file or executable target with the subcommand for chunked
+# regrid weight generation.
+CRWG="ocli chunked-rwg "
+#CRWG="python /home/ubuntu/Dropbox/NESII/project/ocg/git/ocgis/src/ocgis/ocli.py chunked-rwg "
+
+# An optional execution prefix.
+EXEC_PREFIX=""
+#EXEC_PREFIX="mpirun -n `nproc`"
+
+###############################################################################
+
+# Generate the weights using the spatially subset source field and destination
+# field.
+
+${EXEC_PREFIX} ${CRWG} --source ${SRC} --destination ${DST} \
+ --esmf_regrid_method CONSERVE --nchunks_dst ${NCHUNKS_DST} --wd ${CHUNKDIR} \
+ --weight ${WEIGHTS} --persist --esmf_src_type ${SRCTYPE} --esmf_dst_type ${DSTTYPE} \
+ --src_resolution ${SRC_MAXSPATIALRES} --dst_resolution ${DST_MAXSPATIALRES} --verbose

examples/CTSM-MapData-Workflow/get_grid_spatial_resolution.py

@@ -0,0 +1,20 @@
+import ocgis
+
+# Path to the file of interest
+PATH = "/home/benkoziol/Dropbox/dtmp/ctsm-grids/SCRIPgrid_4x5_nomask_c110308.nc"
+# The metadata/IO driver for the data file.
+DRIVER="netcdf-scrip"
+
+# The request dataset provides metadata for a field.
+rd = ocgis.RequestDataset(PATH, driver=DRIVER)
+# The field is similar to ESMF Field and provides access to grids, etc. It can also hold multiple data variables.
+field = rd.create_field()
+print("Average spatial resolution: {}".format(field.grid.resolution))
+print("Maximum spatial resolution: {}".format(field.grid.resolution_max))
+
+#-----------------------------------------------------------------------------------------------------------------------
+
+print("\nDo a simple data file inspection...")
+rd.inspect()
+print("\nThis is the OCGIS interpretation of the metadata (can be customized)...")
+rd.dimension_map.pprint(as_dict=True)

src/ocgis/spatial/grid_chunker.py

@@ -505,8 +505,9 @@ def iter_src_grid_subsets(self, yield_dst=False, yield_idx=None):
                     else:
                         target_grid = dst_grid_subset
 
-                    # Try to reduce the coordinates in the case of unstructured grid data.
-                    if hasattr(target_grid, 'reduce_global') and Topology.POLYGON in target_grid.abstractions_available:
+                    # Try to reduce the coordinates in the case of unstructured grid data. Ensure the data also has a
+                    # coordinate index. SCRIP grid files, for example, do not have a coordinate index like UGRID.
+                    if hasattr(target_grid, 'reduce_global') and Topology.POLYGON in target_grid.abstractions_available and target_grid.cindex is not None:
                         ocgis_lh(logger='grid_chunker', msg='starting reduce_global for dst_grid_subset',
                                  level=logging.DEBUG)
                         target_grid = target_grid.reduce_global()