diff --git a/resources/doc/tutorials/annotations.md b/resources/doc/tutorials/annotations.md
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@@ -0,0 +1,65 @@
+This page is part of the dwv [architecture](./tutorial-architecture.html) description and
+describes the dwv annotations.
+
+Summary:
+
+- [DICOM SR](#dicom-sr)
+
+## DICOM SR
+
+The DICOM SR strucutre used to store annotations is based on the 'DICOM SR for communicating planar annotations'
+document from David A. Clunie ([ref](https://docs.google.com/document/d/1bR6m7foTCzofoZKeIRN5YreBrkjgMcBfNA7r9wXEGR4/edit?tab=t.0)).
+
+```bash
+CONTAINER: (125007, DCM, 'Measurement Group') =
+- (CONTAINS) SCOORD: (111030, DCM, 'Image Region') = POLYLINE {34.10658264160156,117.9686508178711,34.10658264160156,151.67398071289062,70.21943664550781,151.67398071289062,70.21943664550781,117.9686508178711,34.10658264160156,117.9686508178711}
+  - (SELECTED FROM) IMAGE: (121324, DCM, 'Source Image') = 1.3.12.2.1107.5.2.32.35162.2012021516012434416358178 (class: )
+  - (HAS PROPERTIES) UIDREF: (112039, DCM, 'Tracking Identifier') = kfszhdxf288
+  - (HAS PROPERTIES) TEXT: (125309, DCM, 'Short label') = {surface}
+  - (HAS PROPERTIES) TEXT: (718499004, SCT, 'Color') = #ed333b
+  - (CONTAINS) NUM: (103355008, SCT, 'Width') = 36.11285266457679 (mm, UCUM, 'Millimeter')
+  - (CONTAINS) NUM: (121207, DCM, 'Height') = 33.70532915360501 (mm, UCUM, 'Millimeter')
+  - (CONTAINS) NUM: (42798000, SCT, 'Area') = 12.171955857352025 (cm2, UCUM, 'Square centimeter')
+  - (CONTAINS) NUM: (113051, DCM, 'Pixel by pixel Minimum') = 5 (1, UCUM, 'No units')
+  - (CONTAINS) NUM: (113048, DCM, 'Pixel by pixel Maximum') = 453 (1, UCUM, 'No units')
+  - (CONTAINS) NUM: (113049, DCM, 'Pixel by pixel mean') = 196.90849673202615 (1, UCUM, 'No units')
+- (CONTAINS) SCOORD: (111030, DCM, 'Image Region') = POLYLINE {63.487998962402344,111.10399627685547,63.487998962402344,158.20799255371094,117.76000213623047,158.20799255371094,117.76000213623047,111.10399627685547,63.487998962402344,111.10399627685547}
+  - (SELECTED FROM) IMAGE: (121324, DCM, 'Source Image') = 1.3.12.2.1107.5.2.32.35162.2012021516012434416358178 (class: )
+  - (HAS PROPERTIES) UIDREF: (112039, DCM, 'Tracking Identifier') = lldc837468f
+  - (HAS PROPERTIES) TEXT: (125309, DCM, 'Short label') = {surface}
+  - (HAS PROPERTIES) TEXT: (718499004, SCT, 'Color') = #ff7800
+  - (HAS PROPERTIES) SCOORD3D: (128773, DCM, 'Reference Geometry') = MULTIPOINT {52.94638442993164,-73.748046875,108.52542114257812,-1,0,0,0,0,-1}
+  - (CONTAINS) NUM: (103355008, SCT, 'Width') = 54.272000000000006 (mm, UCUM, 'Millimeter')
+  - (CONTAINS) NUM: (121207, DCM, 'Height') = 47.10400000000001 (mm, UCUM, 'Millimeter')
+  - (CONTAINS) NUM: (42798000, SCT, 'Area') = 25.56428288000001 (cm2, UCUM, 'Square centimeter')
+  - (CONTAINS) NUM: (113051, DCM, 'Pixel by pixel Minimum') = 4 (1, UCUM, 'No units')
+  - (CONTAINS) NUM: (113048, DCM, 'Pixel by pixel Maximum') = 597 (1, UCUM, 'No units')
+  - (CONTAINS) NUM: (113049, DCM, 'Pixel by pixel mean') = 166.2642166344294 (1, UCUM, 'No units')
+- (CONTAINS) SCOORD: (111030, DCM, 'Image Region') = POLYLINE {66.55999755859375,28.15999984741211,66.55999755859375,70.14399719238281,114.68800354003906,70.14399719238281,114.68800354003906,28.15999984741211,66.55999755859375,28.15999984741211}
+  - (SELECTED FROM) IMAGE: (121324, DCM, 'Source Image') = 1.3.12.2.1107.5.2.32.35162.2012021516012434416358178 (class: )
+  - (HAS PROPERTIES) UIDREF: (112039, DCM, 'Tracking Identifier') = 1qe1r1zue8o
+  - (HAS PROPERTIES) TEXT: (125309, DCM, 'Short label') = {surface}
+  - (HAS PROPERTIES) TEXT: (718499004, SCT, 'Color') = #33d17a
+  - (HAS PROPERTIES) SCOORD3D: (128773, DCM, 'Reference Geometry') = MULTIPOINT {61.11238098144531,-151.4111328125,-13.127891540527344,-1,0,0,0,1,0}
+  - (CONTAINS) NUM: (103355008, SCT, 'Width') = 48.128 (mm, UCUM, 'Millimeter')
+  - (CONTAINS) NUM: (121207, DCM, 'Height') = 41.983999999999995 (mm, UCUM, 'Millimeter')
+  - (CONTAINS) NUM: (42798000, SCT, 'Area') = 20.206059519999997 (cm2, UCUM, 'Square centimeter')
+  - (CONTAINS) NUM: (113051, DCM, 'Pixel by pixel Minimum') = 3 (1, UCUM, 'No units')
+  - (CONTAINS) NUM: (113048, DCM, 'Pixel by pixel Maximum') = 477 (1, UCUM, 'No units')
+  - (CONTAINS) NUM: (113049, DCM, 'Pixel by pixel mean') = 125.14930555555556 (1, UCUM, 'No units')
+```
+
+Example DICOM SR file with 3 rectangles: 1 on the acquisition plane and 2 on other planes. The `Reference Geometry` code is used to position annotations that are not on the acquisition plane.
+
+SCOORD items are translated according to their `Graphic Type` ((0070,0023) see [part03/sect_C.18.6](https://dicom.nema.org/medical/dicom/current/output/chtml/part03/sect_C.18.6.html#sect_C.18.6.1.2)):
+- Point -> [Point2D](./Point2D.html)
+- Multipoint: not used
+- Polyline ->
+  - [Line](./Line.html): if open shape and 2 points
+  - [Protractor](./Protractor.html): if open shape and 3 points
+  - [Rectangle](./Rectangle.html): if closed shape with 5 points that form 4 perpendicular lines
+  - [ROI](./ROI.html): if closed shape and not rectangle
+- Circle -> [Circle](./Circle.html)
+- Ellipse -> [Ellipse](./Ellipse.html)
+
+Closed shapes are polylines that have the same point as first and last item in their point list.
diff --git a/resources/doc/tutorials/architecture.md b/resources/doc/tutorials/architecture.md
index 5d3db8a140..714af3d850 100644
--- a/resources/doc/tutorials/architecture.md
+++ b/resources/doc/tutorials/architecture.md
@@ -3,3 +3,4 @@ This page is the entry point for the dwv architecture description. See:
 - [Data load](./tutorial-data-load.html)
 - [Layout](./tutorial-layout.html)
 - [View creation](./tutorial-view-create.html)
+- [Annotations](./tutorial-annotations.html)
\ No newline at end of file