Example reading THREDDS NCSS as point in Python



In [1]:

    
%matplotlib inline



In [2]:

    
import pandas as pd

First generate a sample RESTful URL using the NCSS Web Form: http://data.ncof.co.uk/thredds/ncss/METOFFICE-NWS-AF-WAV-HOURLY/pointDataset.html



In [3]:

    
url = 'http://data.ncof.co.uk/thredds/ncss/METOFFICE-NWS-AF-WAV-HOURLY?var=VHM0&var=VHM0_SW1&var=VHM0_WW&latitude=61.15&longitude=-9.5&time_start=2017-06-02T00%3A00%3A00Z&time_end=2017-06-17T23%3A00%3A00Z&accept=csv'

Once you have a sample URL, it's easy to create a different URL programmatically



In [4]:

    
latitude = 61.15
longitude = -9.5
time_start = '2017-06-02T00:00:00Z'
time_end =   '2017-06-17T23:00:00Z'



In [5]:

    
url = 'http://data.ncof.co.uk/thredds/ncss/METOFFICE-NWS-AF-WAV-HOURLY?var=VHM0&var=VHM0_SW1&var=VHM0_WW&latitude={}&longitude={}&time_start={}&time_end={}&accept=csv'.format(latitude,longitude,time_start,time_end)



In [6]:

    
df = pd.read_csv(url, parse_dates=True, index_col=0, na_values=[-32767.0], 
        skiprows=[0], names=['Lon','Lat','SigHeight(m)','Swell(m)','Wind Waves(m)'])



In [7]:

    
# drop lon,lat columns
df = df.drop(df.columns[[0,1]], axis=1)



In [8]:

    
df.head()









    Out[8]:







  
    
      
      SigHeight(m)
      Swell(m)
      Wind Waves(m)
    
  
  
    
      2017-06-02 00:00:00
      329.0
      291.0
      138.0
    
    
      2017-06-02 01:00:00
      332.0
      300.0
      124.0
    
    
      2017-06-02 02:00:00
      334.0
      310.0
      105.0
    
    
      2017-06-02 03:00:00
      335.0
      313.0
      99.0
    
    
      2017-06-02 04:00:00
      334.0
      314.0
      91.0



In [9]:

    
# Ugh, NCSS apparently ignores the scale_factor. Shite!  I'll report this bug, but in the meantime...
df = df/100.



In [10]:

    
df.head()









    Out[10]:







  
    
      
      SigHeight(m)
      Swell(m)
      Wind Waves(m)
    
  
  
    
      2017-06-02 00:00:00
      3.29
      2.91
      1.38
    
    
      2017-06-02 01:00:00
      3.32
      3.00
      1.24
    
    
      2017-06-02 02:00:00
      3.34
      3.10
      1.05
    
    
      2017-06-02 03:00:00
      3.35
      3.13
      0.99
    
    
      2017-06-02 04:00:00
      3.34
      3.14
      0.91



In [11]:

    
df.plot(figsize=(12,4),grid='on');

	SigHeight(m)	Swell(m)	Wind Waves(m)
2017-06-02 00:00:00	329.0	291.0	138.0
2017-06-02 01:00:00	332.0	300.0	124.0
2017-06-02 02:00:00	334.0	310.0	105.0
2017-06-02 03:00:00	335.0	313.0	99.0
2017-06-02 04:00:00	334.0	314.0	91.0

	SigHeight(m)	Swell(m)	Wind Waves(m)
2017-06-02 00:00:00	3.29	2.91	1.38
2017-06-02 01:00:00	3.32	3.00	1.24
2017-06-02 02:00:00	3.34	3.10	1.05
2017-06-02 03:00:00	3.35	3.13	0.99
2017-06-02 04:00:00	3.34	3.14	0.91