Hydrology example from the Vistula catchment in Poland

The Vistula catchment is the largest catchment in Poland, with an area of 194,424 km2. This notebook shows how a hydrological model can evaluated using ModelSkill.

from pathlib import Path
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import modelskill as ms
fldr = Path("../data/Vistula")
df = pd.read_csv(fldr / "stations.csv", index_col=0)
df
Station Long Lat Area
Id
6458010 VISTULA (TCZEW) 18.80556 54.08722 193922.9
6458500 VISTULA (WARSAW (WARSZAWA)) 21.03250 52.24750 84945.1
6458753 PILICA (PRZEDBORZ) 19.87528 51.08944 2550.1
6458715 WIEPRZ (LUBARTOW) 22.64361 51.49806 6389.8
6458713 WIEPRZ (KRASNYSTAW) 23.17667 50.98528 3010.2
6458520 KAMIENNA (KUNOW) 21.27889 50.96194 1110.4
6458460 VISTULA (SANDOMIERZ) 21.74611 50.67250 31809.9
6458450 VISTULA (SZCZUCIN) 21.07722 50.32694 23869.3
6458406 DUNAJEC (NOWY SACZ) 20.68722 49.62722 4337.4
6158100 POPRAD (CHMELNICA) 20.73023 49.28918 1262.0
6458950 WISLOK (TRYNCZA) 22.54722 50.16222 3523.6
6458863 PISA (PTAKI) 21.79250 53.39306 3575.7
6458805 NAREW (SURAZ) 22.95500 52.94889 3425.3
6458924 LIWIEC (LOCHOW) 21.67833 52.51000 2471.4
6458555 KRZNA (MALOWA GORA) 23.46750 52.10361 3041.9 
def get_comparer(df, mods, id):
    """Get a Comparer object for a given model and station id"""
    q = ms.Quantity(name="Discharge", unit="m3/s")

    # create Observation object
    fp = fldr / mods[0] / f"{id}.csv"
    dfd = pd.read_csv(fp, index_col=0, parse_dates=True)
    o = ms.PointObservation(dfd, item="Qobs", name=df.loc[id].Station,
                            x=df.loc[id].Long, y=df.loc[id].Lat, quantity=q)
    
    # create ModelResult objects
    mm = []
    for m in mods:
        fp = fldr / m / f"{id}.csv"
        dfd = pd.read_csv(fp, index_col=0, parse_dates=True)
        mm.append(ms.PointModelResult(dfd, item="Qsim", name=m, quantity=q))
    
    return ms.match(obs=o, mod=mm)

Compare a single observation with two model results

cmp = get_comparer(df, ["sim1","sim2"], df.index[0])
cmp
<Comparer>
Quantity: Discharge [m3/s]
Observation: VISTULA (TCZEW), n_points=3653
Model(s):
0: sim1
1: sim2

Plots

timeseries, scatter, boxplot, hist, kde, qq, taylor

cmp.plot.timeseries();

cmp.sel(model="sim1").plot.scatter();

Summary statistics

# set default metrics
ms.options.metrics.list = ["kge", "cc"]
cmp.skill().round(3)
n kge cc
model observation
sim1 VISTULA (TCZEW) 3653 0.617 0.794
sim2 VISTULA (TCZEW) 3653 0.809 0.829

Statistics aggregated by month

cmp.data["month"] = cmp.time.to_series().dt.month
cmp.skill(by=["model","month"]) #["kge"].plot.bar();
observation n kge cc
model month
sim1 1 VISTULA (TCZEW) 310 0.385138 0.440905
2 VISTULA (TCZEW) 283 0.578280 0.803975
3 VISTULA (TCZEW) 310 0.454622 0.730561
4 VISTULA (TCZEW) 300 0.509017 0.834517
5 VISTULA (TCZEW) 310 0.575944 0.697614
6 VISTULA (TCZEW) 300 0.344820 0.493330
7 VISTULA (TCZEW) 310 0.052140 0.298390
8 VISTULA (TCZEW) 310 0.219232 0.667376
9 VISTULA (TCZEW) 300 0.376622 0.552289
10 VISTULA (TCZEW) 310 0.626824 0.717061
11 VISTULA (TCZEW) 300 0.643888 0.741710
12 VISTULA (TCZEW) 310 0.288263 0.452674
sim2 1 VISTULA (TCZEW) 310 0.580579 0.622109
2 VISTULA (TCZEW) 283 0.844779 0.887547
3 VISTULA (TCZEW) 310 0.669936 0.767161
4 VISTULA (TCZEW) 300 0.764530 0.809858
5 VISTULA (TCZEW) 310 0.487875 0.655435
6 VISTULA (TCZEW) 300 0.496136 0.695364
7 VISTULA (TCZEW) 310 0.235510 0.540092
8 VISTULA (TCZEW) 310 0.269188 0.773781
9 VISTULA (TCZEW) 300 0.526274 0.741995
10 VISTULA (TCZEW) 310 0.719504 0.863399
11 VISTULA (TCZEW) 300 0.721616 0.840079
12 VISTULA (TCZEW) 310 0.506460 0.560932 
cmp.skill(by=["model","month"])["kge"].plot.line()
plt.xlabel("Month")
plt.xticks(np.arange(1,13), ["Jan","Feb","Mar","Apr","May","Jun","Jul","Aug","Sep","Oct","Nov","Dec"]);

Compare multiple observations with two model results

# loop through all stations in df and create a Comparer for each
cmps = []
for id in df.index:
   try:
      cmps.append(get_comparer(df, ["sim1","sim2"], id))
   except ValueError as e:
      pass
cc = ms.ComparerCollection(cmps)
cc   
<ComparerCollection>
Comparers:
0: VISTULA (TCZEW) - Discharge [m3/s]
1: PILICA (PRZEDBORZ) - Discharge [m3/s]
2: WIEPRZ (LUBARTOW) - Discharge [m3/s]
3: WIEPRZ (KRASNYSTAW) - Discharge [m3/s]
4: KAMIENNA (KUNOW) - Discharge [m3/s]
5: VISTULA (SANDOMIERZ) - Discharge [m3/s]
6: VISTULA (SZCZUCIN) - Discharge [m3/s]
7: DUNAJEC (NOWY SACZ) - Discharge [m3/s]
8: POPRAD (CHMELNICA) - Discharge [m3/s]
9: WISLOK (TRYNCZA) - Discharge [m3/s]
10: PISA (PTAKI) - Discharge [m3/s]
11: NAREW (SURAZ) - Discharge [m3/s]
12: LIWIEC (LOCHOW) - Discharge [m3/s]
13: KRZNA (MALOWA GORA) - Discharge [m3/s]
cc.skill(by=["model","observation"], metrics="kge")["kge"].plot.barh();

# Average skill over all stations, weighted by sqrt(area)
area = df.set_index("Station").loc[cc.obs_names].Area
cc.mean_skill(weights=np.sqrt(area)).round(3)
n kge cc
model
sim1 51142 0.504 0.709
sim2 51142 0.586 0.717