Transforming coordinates and orientations¶

This guide explains how to transform events with a specific coordinate system and orientation.

Setup¶

Start by loading some event data using the Kloppy module. For the sake of this demonstration, we will use Statsbomb Open Event Data. Initially we will load the dataset using Statsbomb's original co-ordinate system.

In [1]:

from kloppy import statsbomb
from kloppy.domain import SportVUCoordinateSystem

dataset = statsbomb.load_open_data(
    match_id=15946,
    # Optional arguments
    coordinates="statsbomb",
)

from kloppy import statsbomb from kloppy.domain import SportVUCoordinateSystem dataset = statsbomb.load_open_data( match_id=15946, # Optional arguments coordinates="statsbomb", )

/cw/dtaijupiter/NoCsBack/dtai/pieterr/Projects/kloppy/kloppy/_providers/statsbomb.py:83: UserWarning: 

You are about to use StatsBomb public data.
By using this data, you are agreeing to the user agreement. 
The user agreement can be found here: https://github.com/statsbomb/open-data/blob/master/LICENSE.pdf

  warnings.warn(

Filter by shots and convert to Polars DataFrame¶

In [2]:

# Only keep shots
shots = dataset.filter("shot")

# Convert Kloppy dataset to Polars DataFrame
shots.to_df(
    lambda event: {"team_name": str(event.ball_owning_team)},
    "coordinates_*",
    engine="polars",
)

# Only keep shots shots = dataset.filter("shot") # Convert Kloppy dataset to Polars DataFrame shots.to_df( lambda event: {"team_name": str(event.ball_owning_team)}, "coordinates_*", engine="polars", )

Out[2]:

shape: (28, 3)

team_name	coordinates_x	coordinates_y
str	f64	f64
"Barcelona"	111.45	52.85
"Barcelona"	113.85	26.35
"Barcelona"	93.65	34.65
"Deportivo Alavés"	109.15	39.05
"Barcelona"	107.75	24.65
…	…	…
"Deportivo Alavés"	114.45	32.75
"Barcelona"	113.15	31.35
"Barcelona"	105.25	33.35
"Barcelona"	106.55	46.75
"Barcelona"	111.45	36.15

Transform shots data to a new coordinate system and orientation¶

This step transforms the shot events into a new coordinate system - SportVUCoordinateSystem with a pitch length of 105 and width of 68. Please refer the Kloppy User Guide to see other available coordinate systems that are currently supported.

In this case, we set the orientation to STATIC_HOME_AWAY which sets the home team to play from left to right in both periods.

Avialble orientations are as follows:

• BALL_OWNING_TEAM: The team that is currently in possession of the ball plays from left to right.
• ACTION_EXECUTING_TEAM: The team that executes the action plays from left to right. Used in event stream data only. Equivalent to "BALL_OWNING_TEAM" for tracking data.
• HOME_AWAY: The home team plays from left to right in the first period. The away team plays from left to right in the second period.
• AWAY_HOME: The away team plays from left to right in the first period. The home team plays from left to right in the second period.
• STATIC_HOME_AWAY: The home team plays from left to right in both periods.
• STATIC_AWAY_HOME: The away team plays from left to right in both periods.

In [3]:

shots_transformed = shots.transform(
    to_coordinate_system=SportVUCoordinateSystem(pitch_length=105, pitch_width=68),
    to_orientation="STATIC_HOME_AWAY",
)

shots_transformed_polars = shots_transformed.to_df(
    lambda event: {"team_name": str(event.team), "ground": event.team.ground},
    "coordinates_*",
    engine="polars",
)

shots_transformed_polars

shots_transformed = shots.transform( to_coordinate_system=SportVUCoordinateSystem(pitch_length=105, pitch_width=68), to_orientation="STATIC_HOME_AWAY", ) shots_transformed_polars = shots_transformed.to_df( lambda event: {"team_name": str(event.team), "ground": event.team.ground}, "coordinates_*", engine="polars", ) shots_transformed_polars

Out[3]:

shape: (28, 4)

team_name	ground	coordinates_x	coordinates_y
str	enum	f64	f64
"Barcelona"	"home"	97.1625	45.7725
"Barcelona"	"home"	99.3625	21.494167
"Barcelona"	"home"	81.245714	29.1025
"Deportivo Alavés"	"away"	9.945833	34.86925
"Barcelona"	"home"	93.770833	19.935833
…	…	…	…
"Deportivo Alavés"	"away"	5.0875	40.639167
"Barcelona"	"home"	98.720833	26.0775
"Barcelona"	"home"	91.479167	27.910833
"Barcelona"	"home"	92.670833	40.180833
"Barcelona"	"home"	97.1625	30.47725