Legacy Functionality - fastf1.legacy

This module contains the legacy implementation for calculating distance to driver ahead.

inject_driver_ahead() adds ‘DriverAhead’ and ‘DistanceToDriverAhead’ to the position data for all laps of all drivers. This functionality has been replaced with fastf1.core.Telemetry.add_driver_ahead(). The new implementation provides smoother and more accurate results. Additionally, it can be applied to arbitrary slices of data. But it suffers from integration error when used over multiple laps. The legacy implementation has no integration error issues.

It is recommended to use the new version. If necessary, it should be applied lap by lap and the lap data should be concatenated afterwards. Still, the old version can be used if so desired.

The following is an example comparison plot of the legacy version and the new version. It also shows how the two versions can be used.

import fastf1
import fastf1.plotting
import fastf1.legacy
import numpy as np
import matplotlib.pyplot as plt

fastf1.plotting.setup_mpl()

session = fastf1.get_session(2020, 'Italy', 'R')
session.load()

DRIVER = 'VER'  # which driver; need to specify number and abbreviation
DRIVER_NUMBER = '33'
LAP_N = 10  # which lap number to plot

drv_laps = session.laps.pick_driver(DRIVER)
drv_lap = drv_laps[(drv_laps['LapNumber'] == LAP_N)]  # select the lap

# create a matplotlib figure
fig = plt.figure()
ax = fig.add_subplot()

# ############### new
df_new = drv_lap.get_car_data().add_driver_ahead()
ax.plot(df_new['Time'], df_new['DistanceToDriverAhead'], label='new')

# ############### legacy
df_legacy = fastf1.legacy.inject_driver_ahead(session)[DRIVER_NUMBER].slice_by_lap(drv_lap)
ax.plot(df_legacy['Time'], df_legacy['DistanceToDriverAhead'], label='legacy')

plt.legend()
plt.show()

(png, hires.png, pdf)

fastf1.legacy.REFERENCE_LAP_RESOLUTION = 0.667

A distance in meters which indicates the resolution of the reference lap. This reference is used to project car positions and calculate things like distance between cars.

fastf1.legacy.inject_driver_ahead(session)

Add ‘DistanceToDriverAhead’ and ‘DriverAhead’ column to position data of all drivers in session.

Parameters:

session – fastf1.core.Session

Returns:

A dictionary containing fastf1.core.Telemetry for each driver. The telemetry is the same as fastf1.core.Session.pos_data but with ‘DriverAhead’ and ‘DistanceToDriverAhead’ columns added to each drivers telemetry.