diff --git a/Data-model.md b/Data-model.md
index 9329ed7..343daa6 100644
--- a/Data-model.md
+++ b/Data-model.md
@@ -228,6 +228,7 @@ Markers data is stored as an unordered array of objects (so element id is _not_
 * `icon`: `number` - Unicode character (usually an [emoji](https://emojipedia.org/)) to serve as an icon
 * `x`: `number` - marker x coordinate
 * `y`: `number` - marker y coordinate
+* `cell`: `number` - cell id, used to prevent multiple markers generation in the same cell
 * `type`: `string` - marker type. If set, style changes will be applied to all markers of the same type. Optional
 * `size`: `number` - marker size in pixels. Optional, default value is `30` (30px)
 * `fill`: `string` - marker pin fill color. Optional, default is `#fff` (white)