Court surface
also: hard court · clay court · grass court · indoor
What a tournament is played on: hard, clay, grass or (in older years) carpet, and whether it is indoors.
Surface changes the game: clay slows the ball and lengthens rallies, grass keeps it low and fast, hard courts sit between. Results, records and ratings split by surface say more about a player than overall numbers do.
ESPN does not publish surfaces, so they come from our own tournament reference, keyed by ESPN's tournament id with the years a tournament moved surface (Madrid went from indoor hard to clay in 2009, Stuttgart from clay to grass in 2015). A tournament the reference cannot place has a null surface and is left out of every surface split rather than guessed.
Indoor hard and outdoor hard are both hard here, with indoor as a separate flag. Splitting them is a choice the data supports but the surface field does not make for you.
Where to get it
Related
Court surface from the API
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