Add region selection from file

pcmdi_metrics/io/region_from_file.py

@@ -0,0 +1,34 @@
+import geopandas as gpd
+import regionmask
+import xarray as xr
+import xcdat
+
+def region_from_file(data,rgn_path,attr,feature):
+ # Return data masked from a feature in input file.
+ # Arguments:
+ # data: xcdat dataset
+ # feature: str, name of region
+ # rgn_path: str, path to file
+ # attr: str, attribute name
+
+ lon = data["lon"].data
+ lat = data["lat"].data
+
+ print("Reading region from file.")
+ try:
+ regions_df = gpd.read_file(rgn_path)
+ regions = regionmask.from_geopandas(regions_df,names=attr)
+ mask = regions.mask(lon, lat)
+ # Can't match mask by name, rather index of name
+ val = list(regions_df[attr]).index(feature)
+ except Exception as e:
+ print("Error in creating region subset from file:")
+ raise e
+
+ try:
+ masked_data = data.where(mask == val)
+ except Exception as e:
+ print("Error: Region selection failed.")
+ raise e
+
+ return masked_data