This API is only available when running on Windows 10 build 10586 (released November 2015) or greater.
DPI describes the ratio between device independent pixels (DIPs) and actual physical pixels. The identity DPI value is 96, which means DIPs and pixels are the same.
Sprite batches inherit their DPI from the CanvasDrawingSession they were created from.
For more information, see DPI and DIPs.