# init(xStart:xEnd:y:series:) Creates an area mark that plots values with a horizontal interval and associates it with the specified series. ``` nonisolated init(xStart: PlottableValue, xEnd: PlottableValue, y: PlottableValue, series: PlottableValue) where X : Plottable, Y : Plottable, S : Plottable ``` ## Parameters `xStart` The starting horizontal position for the mark. `xEnd` The ending horizontal position for the mark. `y` The vertical position for the mark. `series` A series to associate the mark with. ## Discussion The initializer behaves like [`init(xStart:xEnd:y:)`](/documentation/Charts/AreaMark/init(xStart:xEnd:y:)), except that you can indicate which region each interval belongs to by providing a value for the `series` input. This enables you to plot more than one region on a single chart. To plot a series of values that have a vertical interval, use [`init(x:yStart:yEnd:series:)`](/documentation/Charts/AreaMark/init(x:yStart:yEnd:series:)) instead. --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)