feat(data-layers): use log values for oc.chlor_a

data/downloads/odp-ftp-oc.sh

@@ -16,5 +16,6 @@ do
 
   curl --silent $FTP_URL > $FILENAME
 
+  python ./data/log-values.py --file $FILENAME --variable chlor_a
   python ./data/drop-unused-vars.py --file $FILENAME --variable chlor_a
 done

data/gdal-colors/colors-chlor_a.txt

@@ -1,5 +1,5 @@
-30 245 245 208
-3 142 211 186
-0.3 34 150 193
-0.03 37 56 159
+1.47, 245, 245, 208
+0.47, 142, 211, 186
+-0.52, 34, 150, 193
+-1.52, 37, 56, 159
 nv 0 0 0 0

data/log-values.py

@@ -0,0 +1,15 @@
+import os
+import xarray as xr
+from argparse import ArgumentParser
+
+parser = ArgumentParser()
+parser.add_argument("-f", "--file", dest="file")
+parser.add_argument("-v", "--variable", dest="variable")
+args = parser.parse_args()
+
+ds = xr.open_dataset(args.file, decode_coords=True, decode_cf=True)
+da = ds[args.variable]
+ds[args.variable] = xr.ufuncs.log10(da)
+
+os.remove(args.file)
+ds.to_netcdf(args.file, format='NETCDF4', mode='w')