成员变量 类型: String # static readonly feet LinearUnits.feet，英尺 Default Value: 'feet' 类型: String # static readonly kilometers LinearUnits.kilometers，千米 Default Value: 'kilometers' 类型: String # static readonly meters LinearUnits.meters，米 Default Value: 'meters' 类型: String # static readonly miles LinearUnits.miles，英里 Default Value: 'miles' 类型: String # static readonly nauticalMiles LinearUnits.nauticalMiles，海里 Default Value: 'nautical-miles' 类型: String # static readonly yards LinearUnits.yards，码 Default Value: 'yards'
