Can't save Impacts when CRS is a pyproj CRS object #706
Description
The Impact.write_hdf5 method fails when the Impact's crs attribute is a pyproj.crs.crs.CRS class.
This is the case when the Impact is created using LitPop exposures from the Data API.
Here is a reproducible example:
from climada.util.api_client import Client
from climada.entity import ImpfTropCyclone, ImpactFuncSet
from climada.engine.impact_calc import ImpactCalc
client = Client()
country = 'KNA'
haz = client.get_hazard('tropical_cyclone', properties={'country_iso3alpha': country, 'climate_scenario': 'rcp45', 'ref_year': '2080'})
exp = client.get_litpop(country)
impf_set = ImpactFuncSet([ImpfTropCyclone.from_emanuel_usa()])
imp = ImpactCalc(exp, impf_set, haz).impact(save_mat=False)
imp.write_hdf5('./deleteme.hdf5')
Giving the error
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
File "/Users/chrisfairless/opt/anaconda3/envs/nccs/lib/python3.9/site-packages/climada/engine/impact.py", line 987, in write_hdf5
write(file, name, value)
File "/Users/chrisfairless/opt/anaconda3/envs/nccs/lib/python3.9/site-packages/climada/engine/impact.py", line 922, in write
return writer(group, name, value)
File "/Users/chrisfairless/opt/anaconda3/envs/nccs/lib/python3.9/site-packages/climada/engine/impact.py", line 934, in write_attribute
group.attrs[name] = value
File "h5py/_objects.pyx", line 54, in h5py._objects.with_phil.wrapper
File "h5py/_objects.pyx", line 55, in h5py._objects.with_phil.wrapper
File "/Users/chrisfairless/opt/anaconda3/envs/nccs/lib/python3.9/site-packages/h5py/_hl/attrs.py", line 103, in __setitem__
self.create(name, data=value)
File "/Users/chrisfairless/opt/anaconda3/envs/nccs/lib/python3.9/site-packages/h5py/_hl/attrs.py", line 180, in create
htype = h5t.py_create(original_dtype, logical=True)
File "h5py/h5t.pyx", line 1663, in h5py.h5t.py_create
File "h5py/h5t.pyx", line 1687, in h5py.h5t.py_create
File "h5py/h5t.pyx", line 1747, in h5py.h5t.py_create
TypeError: Object dtype dtype('O') has no native HDF5 equivalent
The issue appears to be that there's no specific method for reading and writing the CRS to file. The method falls back on the generic method to write any object write_attribute which fails. It looks like we need a dedicated write_crs method.
In the meantime, users running into the issue can try converting the CRS object into a string before saving, or (in 99% of cases) change it to CLIMADA default:
from climada.util.constants import DEF_CRS
imp.crs = DEF_CRS
Note: Exposures.write_hdf5 doesn't have this issue because it uses a different method to convert.