ITF

49 7. SLOPE AND PLANARITY (ITF CS 03/03) Ideally, a tennis court should be a flat surface lying in a single horizontal plane. The court may be sloped for drainage, but the single plane of the surface should always be maintained. The slope should be oriented to minimise its effect on play. Thus, where a court must be sloped for drainage, a slope from side-to-side is preferred (see Figure 6). The slope is determined by measuring the ratio of change in elevation to horizontal distance. Planarity is measured relative to a hypothetical plane parallel to the slope of the court. Figure 6. Preferred orientation of slope (side-to-side), if necessary. Apparatus Test apparatus consists of: A distance-measuring device, calibrated to ± 0.05%, such as a laser distance meter or a steel tape. A surveyor's level, calibrated to ± 1 mm/10 m, and a measuring staff, calibrated to ± 0.25 mm. The level may be either a self-levelling rotary laser, which sweeps out a horizontal plane with a beam of visible or infrared light, or an optical level, where the plane is defined by the horizontal axis of the instrument. Calibration of apparatus The distance-measuring device and measuring staff must be checked against known standards. This should be carried out at appropriate intervals (typically annually) or if there is any reason to suspect that the device is inaccurate and/or has been damaged (e.g. if a laser distance meter has been dropped or left in the rain, or a steel tape has become kinked).

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