Winkel I projection is the average of two projections, Sinusoidal and Equirectangular, in both x and y coordinates, and is "not free of distortion at any point".

Construction | Pseudocylinder |

Property | Neither conformal nor equal-area |

Meridians | Central meridian is a straight line 0.61 the length of the Equator. Other meridians are sinusoidal curves that are equally spaced and concave toward the central meridian. |

Parallels | Parallels are equally spaced. |

Graticule spacing | See Meridians and Parallels. Pole lines are 0.61 the length of the Equator. Symmetry exists about the central meridian or the Equator. |

Linear scale | Scale is true along latitudes 50° 28’ N and S. Scale is constant along any given latitude as well as the latitude of the opposite sign. |

Uses | World maps. |

Source: Snyder and Voxland, 1989

Winkel I Projection

Source: Snyder and Voxland, 1989