update parcellation map pages

docs/basic_functionalities/exploring_3d_parcellation_maps.md

 # Exploring 3D Parcellation Maps
 
-Based on the displayed reference template and brain parcellation, siibra-explorer provides functionalities for downloading the volumes, browsing brain region hierarchies, and retrieving various data features, such as regional distributions of cells and neurotransmitters structural, or/and functional connectivity between brain regions. 
+In the case of a volumetric template, siibra-explorer combines a rotatable 3D surface view of a brain volume with three planar views of orthogonal image planes (coronal, sagittal, horizontal). It can visualize very large brain volumes in the Terabyte range.
 
-Depending on the type of the selected reference template, the view differs.
+![](https://data-proxy.ebrains.eu/api/v1/buckets/reference-atlas-data/static/julichbrain_bigbrain_4panel.png){: style="width:700px" }
 
-## Navigation Volumetric Maps
+Each planar view allows zooming (`[mouse-wheel]`) and panning (`[mouse-drag]`). 
+You can change the default planes to arbitrary oblique cutting planes using `<shift> + [mouse-drag]`. This is especially useful for inspecting cortical layers and brain regions in their optimal 3D orientation when browsing a microscopic volume.
+In addition, each planar view can be maximized to full screen (`[mouse-over]` then `<click>` on `[ ]` icon) to behave like a 2D image viewer.
+After maximizing a view, `[space]` cycles between the four available views.
 
-In the case of a volumetric template, siibra-explorer combines a rotatable 3D surface view of a brain volume with three planar views of orthogonal image planes (coronal, sagittal, horizontal). It can visualize very large brain volumes in the terabyte range.
+![](https://data-proxy.ebrains.eu/api/v1/buckets/reference-atlas-data/static/julichbrain_bigbrain_coronal.png){: style="width:700px" }
 
-![](https://data-proxy.ebrains.eu/api/v1/buckets/reference-atlas-data/static/julichbrain_bigbrain_4panel.png)
 
-Each planar view allows zooming (`[mouse-wheel]`) and panning (`[mouse-drag]`), and can be maximized to full screen (`[mouse-over]` then `<click>` on `[ ]` icon) to behave like a 2D image viewer. You can select arbitrary non-orthogonal cutting planes (`<shift> + [mouse-drag]`), so that cortical layers may be inspected in their optimal 3D orientation when browsing a microscopic brain volume.
+The rotable 3D overview can be zoomed (`[mouse-wheel]`) and rotated (`[mouse-drag]`) independently.
+However, its resolution is locked to always show the whole brain and provide the 3D topographical context even when zoomed in deeply to the planar views. 
+Per default, it indicates the currently selected cutting planes by removing the octant facing towards the observer. This functionality can be disabled by clicking the settings icon in the bottom right.
 
-![](https://data-proxy.ebrains.eu/api/v1/buckets/reference-atlas-data/static/julichbrain_bigbrain_coronal.png)
+In the case of a pure surface space, no planes are shown. siibra-explorer then shows a single 3D view presenting the surface of the reference template. It uses the same controls as the 3D overview of the volumetric view for zooming and rotation, but does not restrict the zoom level.
 
-Users can explore the reference atlas at higher resolution (if available) by zooming in on the planar views.
-
-Independent of the available resolution of the volumetric reference atlas, the resolution of the 3D view is locked to always show the whole brain and provide the 3D topographical context. 
-
-## Navigating surface maps
-
-In the case of a surface template, siibra-explorer shows a single view presenting the surface of the reference template.
-
-![](https://data-proxy.ebrains.eu/api/v1/buckets/reference-atlas-data/static/julichbrain_fsaverage.png)
+![](https://data-proxy.ebrains.eu/api/v1/buckets/reference-atlas-data/static/julichbrain_fsaverage.png){: style="width:700px" }
 

docs/basic_functionalities/selecting_parcellation_maps.md

@@ -6,9 +6,5 @@ On the bottom left of the viewer, you find selectors for choosing the species, r
 
 When selecting a species, a default reference space and parcellation will be automatically preselected.
 If you switch to a different reference space, `siibra-explorer` will first check if a map of the currently selected parcellation is available for the chosen space. If it is not, you will be asked to select a different parcellation.
-Vice versa, when selecting a different parcellation which is not available in the currently selected reference space, you 
+Vice versa, when selecting a parcellation which is not available as a map in the currently selected reference space, you will be asked to select a different space.
 
-Maps from the Multilevel Human Atlas can be available in different reference spaces and resolutions: We provide volumetric (ICBM 2009c nonl asym, MNI Colin 27), high-resolution volumetric (BigBrain) and surface-based (fsaverage) reference spaces. If you change the reference space, you might need to change the parcellation, if it is not mapped in the selected reference space. The system will give you the advice.
-
-
-(TBD)

mkdocs.yml

@@ -25,7 +25,6 @@ nav:
   - Basic Functionalities:
     - Organisation of user interface: 'basic_functionalities/overview_of_ui.md'
     - Selecting parcellation maps: 'basic_functionalities/selecting_parcellation_maps.md'
-    - Selecting parcellation maps: 'basic_functionalities/selecting_parcellation_maps.md'
     - Exploring 3D parcellation maps: 'basic_functionalities/exploring_3d_parcellation_maps.md'
     - Keyboard shortcuts: 'basic_functionalities/helperOnePager.md'
     - Storing and sharing 3D views: 'basic_functionalities/storing_and_sharing_3d_views.md'