diff --git a/Data-model.md b/Data-model.md
index f5f3921..9217730 100644
--- a/Data-model.md
+++ b/Data-model.md
@@ -225,13 +225,16 @@ Rivers data is stored as an unordered array of objects (so element id is _not_ t
 ## Markers [WIP]
 Markers data is stored as an unordered array of objects (so element id is _not_ the array index). Object structure:
 * `i`: `number` - marker id. `'marker' + i` is used as svg element id and marker reference in `notes` object 
-* `icon`: `number` - unicode character
-* `type`: `string` - optional, used only for auto-generated markers
+* `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
-* `dx`: `number` - marker icon x shift
-* `dy`: `number` - marker icon y shift
-* `size`: `number` - marker icon size
+* `type`: `string` - marker group, used for auto-generated markers. Optional
+* `size`: `number` - marker size in pixels. Optional, default value is `30px`
+* `hidden`: `boolean`: `true` if marker should not be rendered. Optional, default is `false` (visible)
+* `bare`: `boolean`: `true` if marker should be rendered without pin (bubble). Optional, default is `false` (pinned)
+* `dx`: `number` - icon x shift percent. Optional, default is `50%` (center)
+* `dy`: `number` - icon y shift percent. Optional, default s `50%` (center)
+* `px`: `number` - icon font-size in pixels. Optional, default is `12px`
 
 ## Routes
 Routes data is not in data model, but can be retrieved directly from svg `routes` element and `pack.cells.roads` array.