example test error

[jasonjee]

hi, i got a error when i ran "Log based System Identification and Control Design" in Cell 1.
Well, how can i fix the error? Need help, thx~

---

KeyError Traceback (most recent call last)
in ()
1 get_ipython().run_line_magic('load_ext', 'autoreload')
2 get_ipython().run_line_magic('autoreload', '2c')
----> 3 import px4tools
4 import px4tools.logsysid
5 import pandas

~/miniconda3/lib/python3.6/site-packages/px4tools/init.py in ()
2
3 try:
----> 4 from .mapping import *
5 except ImportError as ex:
6 print(ex)

~/miniconda3/lib/python3.6/site-packages/px4tools/mapping.py in ()
6
7 from future import print_function
----> 8 from mpl_toolkits.basemap import Basemap
9 import pandas
10

~/miniconda3/lib/python3.6/site-packages/mpl_toolkits/basemap/init.py in ()
144
145 # create dictionary that maps epsg codes to Basemap kwargs.
--> 146 pyproj_datadir = os.environ['PROJ_LIB']
147 epsgf = open(os.path.join(pyproj_datadir,'epsg'))
148 epsg_dict={}

~/miniconda3/lib/python3.6/os.py in getitem(self, key)
667 except KeyError:
668 # raise KeyError with the original key value
--> 669 raise KeyError(key) from None
670 return self.decodevalue(value)
671

KeyError: 'PROJ_LIB'