Autoscale utility for CRISPCA files or other simple netcdf float arrays

pca/l1b-pcs/autoscale.py

@@ -76,8 +76,8 @@ class Autoscale:
     def attrs(self):
         """ CF attributes and fill value
         """
-        return {'scale': np.array(self.scale, dtype=self.dtype),
-                'offset': np.array(self.offset, dtype=self.dtype),
+        return {'scale_factor': np.array(self.scale, dtype=self.dtype),
+                'add_offset': np.array(self.offset, dtype=self.dtype),
                 '_FillValue': self.vnan
                 }
 

pca/l1b-pcs/nc_copy_autoscale.py

+#!/usr/bin/env python3
+
+import netCDF4 as nc4
+from pathlib import Path
+from autoscale import Autoscale
+
+
+def copy(input_fn: Path, output_fn: Path):
+    nci = nc4.Dataset(input_fn, 'r')
+    nco = nc4.Dataset(output_fn, 'w')
+    for dname, dextent in nci.dimensions.items():
+        nco.createDimension(dname, len(dextent))
+    for gname in nci.ncattrs():
+        nco.setncattr(gname, getattr(nci, gname))
+    for vname, vdata in nci.variables.items():
+        nd = vdata[:]
+        sc = Autoscale(nd)
+        sca = sc.attrs
+        scale = sca['scale_factor']
+        offset = sca['add_offset']
+        print(f"scaling {vname} as m={scale} b={offset}")
+        ovdata = nco.createVariable(vname, sc.vdtype, vdata.dimensions, fill_value=sc.vnan, zlib=True)
+        ovdata.set_auto_scale(False)
+        ovdata.setncattr('scale_factor', scale)
+        ovdata.setncattr('add_offset', offset)
+        for attr_name in vdata.ncattrs():
+            if attr_name != '_FillValue':
+                setattr(ovdata, attr_name, vdata[attr_name])
+        ovdata[:] = sc.convert(nd)
+    nco.close()
+    nci.close()
+
+
+if __name__ == '__main__':
+    import sys
+
+    ip = Path(sys.argv[1])
+    op = Path(sys.argv[2])
+    assert not op.exists()
+    copy(ip, op)