Wrong filter bot calculated from pb length and surface level

[TobiasMulder]

the bottom of the filter in mNAP in line 810 should be calculated with the 'HOOGTE_BOV_BUIS'.
If only 'HOOGTE_MAAIVELD' is present than the current code gives an estimation but this should be made clear.
The name BOVENKANT_FILTER is confusing by the way. this should be changes to filter_length or FILTERLENGTE

so perhaps with if else statement.
# Calculate the statistics of the meetgegevens.
df_pbStats = self.PRW.PbStats(df_meetgegevens)
If df_pbs['HOOGTE_BOV_BUIS']:
# Present the statistics with some peilbuis gegevens
ond_filt = df_pbs['HOOGTE_BOV_BUIS'].to_numpy(dtype=np.float) -
df_pbs['BOVENKANT_FILTER'].to_numpy(dtype=np.float) -
df_pbs['LENGTE_BUIS'].to_numpy(dtype=np.float)
bov_filt = df_pbs['HOOGTE_BOV_BUIS'].to_numpy(dtype=np.float) -
df_pbs['BOVENKANT_FILTER'].to_numpy(dtype=np.float)
else:
# Present the statistics with some peilbuis gegevens
ond_filt = df_pbs['HOOGTE_MAAIVELD'].to_numpy(dtype=np.float) -
df_pbs['LENGTE_BUIS'].to_numpy(dtype=np.float)
bov_filt = df_pbs['HOOGTE_MAAIVELD'].to_numpy(dtype=np.float) -
df_pbs['LENGTE_BUIS'].to_numpy(dtype=np.float) + df_pbs['BOVENKANT_FILTER'].to_numpy(dtype=np.float)