# init(xStart:xEnd:y:) Creates an area mark that plots values with a horizontal interval. ``` nonisolated init(xStart: PlottableValue, xEnd: PlottableValue, y: PlottableValue) where X : Plottable, Y : 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. ## Discussion Use this initializer to create a range area chart with horizontal intervals. For example you can create a region that encompasses all the temperatures over the course of a day, across a number of days: ``` Chart(data) { day in AreaMark( xStart: .value("Minimum Temperature", minimumTemperature), xEnd: .value("Maximum Temperature", day.maximumTemperature), y: .value("Date", day.date) ) } ```  If you want to plot values that have a vertical interval, use [`init(x:yStart:yEnd:)`](/documentation/Charts/AreaMark/init(x:yStart:yEnd:)) 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)