In [1]:
import pandas as pd
import numpy as np
from pathlib import Path
import matplotlib
from IPython.display import HTML
import requests
from datetime import datetime
My first step is to find interesting stations and one of the requirements is to find some that have a good time range coverage so I will evaluate the files downloaded.
Reading the stations coordinates CSV
In [2]:
stations = pd.read_csv(
'../../data/ncdc/ish-history.csv',
skiprows=1,
names=['usaf','wban','stname','ctry','fips','state','call','lat' ,'lon' ,'elev'],
dtype=object)
print (len(stations))
stations[:3]
Out[2]:
Get correct coordinates dividing the lat/lon by 1000 and the elevation by 10. Then generate a unique index and a column that specficies if the id is from a USAF station or from WBAN. Finally drop any station that doesn't have a location to use.
In [3]:
stations['lat'] = stations.lat.apply(lambda lat: float(lat)/1000)
stations['lon'] = stations.lon.apply(lambda lon: float(lon)/1000)
stations['elev'] = stations.elev.apply(lambda e: float(e)/10.0)
In [4]:
stations['id'] = stations.apply(lambda row : "{}-{}".format(row.usaf,row.wban),axis=1)
stations.set_index(['id'],inplace=True)
stations.dropna(how='any',subset=['lat','lon'],inplace=True)
stations.head()
Out[4]:
In [5]:
stations[(stations.usaf == '082840')]
Out[5]:
Instantiate the path where the NCDC data has been downloaded
In [6]:
p = Path('../../data/ncdc')
Check if we have already the stations CSV or generate it from the files. To generate the CSV the name file will be inspected but also a full read of the file will be performed in order to count the number of observations on every station.
In [7]:
gsodCSV = p.joinpath('gsod.csv')
if not gsodCSV.exists():
ops = p.joinpath('raw').joinpath('gsod').glob('**/*.op')
agsod = []
for op in ops:
try:
data = op.name.replace('.op','').split('-')
data.append(sum(1 for line in op.open( encoding='utf8' ))-1)
agsod.append(data)
except UnicodeDecodeError:
print (op.absolute())
dfGsod = pd.DataFrame(data = agsod, columns=['usaf','wban','year','obs'])
dfGsod['id'] = dfGsod.apply(lambda row: "{}-{}".format(row.usaf,row.wban) ,axis=1)
dfGsod = dfGsod.set_index(['id'])
dfGsod[['year','obs']].to_csv(str(gsodCSV))
In [8]:
print ('Reading existing stations per year CSV')
dfGsod = pd.read_csv(str(gsodCSV),index_col=['id'])
print ("{:,} station files".format(len(dfGsod)))
print ("{:,} observations".format(dfGsod.obs.sum()))
dfGsod.head()
Out[8]:
Now study this dataframe, grouping by id and see the total years recorded, max and min
In [9]:
year_groups = dfGsod[['year']].groupby(level=0)
year_count = year_groups.count()
year_max = year_groups.max()
year_min = year_groups.min()
years = pd.concat([year_count,year_max,year_min],axis=1)
years.columns = ['count','max','min']
years.head()
Out[9]:
In [10]:
obs_groups = dfGsod[['obs']].groupby(level=0)
obs_count = obs_groups.sum()
obs_count.head()
Out[10]:
In [11]:
obs_count[(obs_count.index == '082840-99999')]
Out[11]:
Now we can check if the indexes of both data frames are unique and then join them to retreive only the stations with observations
In [12]:
stations.index.is_unique and years.index.is_unique and obs_count.index.is_unique
Out[12]:
In [13]:
scdf = pd.concat([stations[(stations.index=='082840-99999')],years,obs_count],axis=1,join='inner')
scdf.head()
Out[13]:
Finally we can study this dataset and filter the appropriate stations for our study on this first iteration
In [14]:
scdf.to_csv('stations_vlc.csv')
Check if the index of the imported dataframe is unique and then join it with our stations dataset. This join will keep only data on both data frames using the parameter join='inner'.
In [15]:
selections.index.is_unique
In [16]:
scdf['koppen'] = 'BSk'
Filter the observations data set (around 11M records) by the selected stations and generate the file list to read from the observations folder. First we join the stations with the counts, then we move the index to a column and finally we define the path as a concatenation of the year (on a folder) and the file name as the id and the year.
In [17]:
files_to_read = pd.merge(left=dfGsod,right=scdf,left_index=True,right_index=True,)[['year']]
files_to_read['id'] = files_to_read.index
files_to_read['path'] = files_to_read.apply(lambda row: Path('../../data/ncdc/raw/gsod').joinpath("{0}/{1}-{0}.op".format(row.year,row.id)),axis=1)
print ("{} files to read".format(len(files_to_read)))
Read the files defined previously and store the results on a new big data frame and CSV adding the Köppen classification. First we define a couple of helping functions and then we iterate over the files_to_read data frame to read the corresponding CSV and append it to the final CSV file.
In [18]:
def getId(stn,wban):
try:
istn = int(stn)
iwban = int(wban)
return "{:0>6}-{:0>5}".format(istn,iwban)
except ValueError:
print("{}/{}".format(stn,wban))
def getStationByStnWban(stn,wban):
try:
koppen = scdf.loc[getId(stn,wban)].koppen
except KeyError:
koppen = None
return koppen
In [19]:
observationsCSV = p.joinpath('observations_vlc.csv')
if not observationsCSV.exists():
i = 0
acc = 0
for index,row in files_to_read.iterrows():
path = row['path']
if path.exists():
dfObsTemp = pd.read_fwf(
str(path),
colspecs=[(0,7),(7,13),(14,18),(18,22),(25,30),(31,33),(35,41),
(42,44),(46,52),(53,55),(57,63),(64,66),(68,73),(74,76),
(78,84),(84,86),(88,93),(95,100),(102,108),(108,109),
(110,116),(116,117),(118,123),(123,124),(125,130),(132,138)],
skiprows=1,
names=['stn','wban','year','monthday','temp','temp_count',
'dewp','dewp_count','slp','slp_count','stp','stp_count',
'visib','visib_count','wsdp','wsdp_count','mxspd',
'gust','max','max_flag','min','min_flag','prcp','prc_flag','sndp','frshtt']
)
dfObsTemp['koppen'] = dfObsTemp.apply(lambda row: getStationByStnWban(row.stn,row.wban),axis=1)
dfObsTemp.to_csv(str(observationsCSV),mode='a')
i += 1
acc += len (dfObsTemp)
if i % 1000 == 0:
print("{:>8} obs".format(acc))
In [20]:
print ('Reading observations CSV')
dfObs = pd.read_csv(str(observationsCSV),index_col=0)
dfObs = dfObs[(dfObs.stn != 'stn')]
print ("{:,} observations".format(len(dfObs)))
dfObs.head()
Out[20]:
Now that we have the raw dataset, we can start doing management operations. First generate a copy dataframe with only the columns we are interested in.
In [27]:
dfObs2 = dfObs.copy()[['stn','wban','year','monthday','temp','max','min','frshtt','koppen']]
Generate an index using the id station and the date
In [28]:
def getDateTimeFromRow(row):
try:
iyear = int(row.year)
imonth = int("{:0>4}".format(row.monthday)[0:2])
iday = int("{:0>4}".format(row.monthday)[2:4])
return datetime(iyear,imonth,iday)
except ValueError:
return np.nan
dfObs2['id'] = dfObs2.apply(lambda row: getId(row.stn,row.wban) ,axis=1)
dfObs2['date'] = dfObs2.apply(lambda row : getDateTimeFromRow(row),axis=1)
dfObs2.set_index(['id','date'],inplace=True)
The frshtt column needs to be padded with zeros to get all the flags in the correct place. Then is possible to get the occurrence of different weather conditions
In [29]:
dfObs2['frshtt'] = dfObs2.apply(lambda row: "{:0>6}".format(row.frshtt),axis=1)
dfObs2['fog'] = dfObs2['frshtt'].apply(lambda row: row[0:1]=='1')
dfObs2['rain'] = dfObs2['frshtt'].apply(lambda row: row[1:2]=='1')
dfObs2['snow'] = dfObs2['frshtt'].apply(lambda row: row[2:3]=='1')
dfObs2['hail'] = dfObs2['frshtt'].apply(lambda row: row[3:4]=='1')
dfObs2['thunder'] = dfObs2['frshtt'].apply(lambda row: row[4:5]=='1')
dfObs2['tornado'] = dfObs2['frshtt'].apply(lambda row: row[5:6]=='1')
Recode the temperatures columns, replacing the NaN values and afterwards as numerics
In [47]:
dfObs2['tempC'] = dfObs2['temp'].replace('99.9', np.nan)
dfObs2['maxC'] = dfObs2['max'].replace('99.9', np.nan)
dfObs2['minC'] = dfObs2['min'].replace('99.9', np.nan)
dfObs2['tempC'] = dfObs2['tempC'].convert_objects(convert_numeric=True)
dfObs2['maxC'] = dfObs2['maxC'].convert_objects(convert_numeric=True)
dfObs2['minC'] = dfObs2['minC'].convert_objects(convert_numeric=True)
def FtoC(f):
return (f-32)*5/9
dfObs2['tempC'] = dfObs2['tempC'].apply(lambda temp: FtoC(temp))
dfObs2['maxC'] = dfObs2['maxC'].apply(lambda temp: FtoC(temp))
dfObs2['minC'] = dfObs2['minC'].apply(lambda temp: FtoC(temp))
In [49]:
dfObsTemp.to_csv(str(observationsCSV))
Frequency tables for koppen, thunders, tornados that are categorized
In [26]:
dfObs.koppen.value_counts(normalize=True)*100
Out[26]:
In [27]:
dfObs2.tornado.value_counts(normalize=True)*100
Out[27]:
In [28]:
dfObs2.thunder.value_counts(normalize=True)*100
Out[28]:
Categorize the temperatures by quantiles and then make the frequency table to confirm the categorization
In [29]:
dfObs2['temp4']=pd.qcut(dfObs2.tempC, 4, labels=["1=0%tile","2=25%tile","3=50%tile","4=75%tile"])
dfObs2['temp4'].value_counts(normalize=True)*100
Out[29]:
And to get the cuts, we can group by the categorization column and get the max value for every group
In [38]:
group_by_year= dfObs2[['temp4','tempC']].groupby(['temp4'])
group_by_year.max()
Out[38]:
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