Update layout map grid "rotation" properties

docs/user_manual/print_composer/composer_items/composer_map.rst

@@ -282,6 +282,8 @@ Double-click the added grid to rename it.
 To modify a grid, select it and press the :guilabel:`Modify Grid...` button
 to open the :guilabel:`Map Grid Properties` panel and access its configuration options.
 
+.. _grid_appearance:
+
 Grid Appearance
 ...............
 
@@ -343,6 +345,25 @@ section you can prevent a mix of latitude/Y and longitude/X coordinates showing
 on each side when working with rotated maps or reprojected grids.
 Also you can choose to set visible or not each side of the grid frame.
 
+When the map item extent is rotated (from the :guilabel:`Main properties` group)
+or the grid has a different CRS applied, grid lines may not be orthogonal to the map item sides.
+This can result in bad looking of the grid when styled with interior and/or exterior ticks.
+Checking |checkbox| :guilabel:`Follow grid rotation` will align the ticks with grid lines.
+Moreover, you can adjust some more properties:
+
+* :guilabel:`Ticks alignment`: The interior and/or exterior ticks will be parallel
+  to their corresponding grid line.
+  Their alignment can be:
+
+  * **Orthogonal**: ticks on the same side end at one line, parallel to the side.
+    This can result e.g. in some ticks getting longer when with a low angle to the frame.
+  * **Fixed length**: all ticks have the same length, so they may not align
+* :guilabel:`Skip below angle`: prevents displaying ticks for grid lines intersecting the frame border
+  below a specified threshold
+* :guilabel:`Margin from map corner`: prevents displaying ticks too close to the map corners,
+  because they could overlap and/or be out of bounds.
+
+
 .. _Figure_layout_map_frame:
 
 .. figure:: img/map_grid_frame.png
@@ -354,18 +375,43 @@ Coordinates
 ...........
 
 The |checkbox| :guilabel:`Draw coordinates` checkbox allows you to add
-coordinates to the map frame. You can choose the annotation numeric format,
+coordinates to the map frame.
+Displayed values relate to the chosen :ref:`grid interval <grid_appearance>` unit.
+You can choose the annotation numeric format,
 the options range from decimal to degrees, minute and seconds, with or without
 suffix, aligned or not and a custom format using the expression dialog.
 
-You can choose which annotation to show. The options are: show all, latitude
-only, longitude only, or disable(none). This is useful when the map is rotated.
-The annotation can be drawn inside or outside the map frame. The annotation
-direction can be defined as horizontal, vertical ascending or vertical
-descending.
+For each of the :guilabel:`Left`, :guilabel:`Right`, :guilabel:`Top`
+and :guilabel:`Bottom` sides of the grid frame, you can indicate:
+
+* whether to render the coordinates: **Show all**, **Show latitude/Y only**,
+  **Show longitude/X only**, **Disabled**.
+  Showing only Latitude/Y or Longitude/X values in the divisions
+  helps prevent a mix of latitude/Y and longitude/X coordinates showing
+  on each side when working with rotated maps or reprojected grids.
+* the relative position of the text to the grid frame:
+  **Outside frame** or **Inside frame**
+* the placement and orientation of the annotation:
+
+  * **Horizontal**
+  * **Vertical ascending**, **Vertical descending**
+  * **Boundary direction**
+  * **Above tick**, **On tick**, **Under tick** when a tick-based frame is used
+
+You can also define the :guilabel:`Font` properties (font, size, color, buffer,...)
+the :guilabel:`Distance to the map frame` and the :guilabel:`Coordinate precision`
+(number of decimals) for the drawn annotations.
+
+|unchecked| :guilabel:`Follow grid rotation`: available when the map extent is rotated
+or the grid is reprojected, it helps you adjust the annotations placement.
+Depending on the selected placement mode, the annotations are also rotated:
+
+* :guilabel:`Annotations alignment`: it can be **Orthogonal** or of **Fixed length**
+* :guilabel:`Skip below angle`: prevents displaying annotations for grid lines
+  intersecting the frame border below a specified threshold
+* :guilabel:`Margin from map corner`: prevents displaying annotations too close to the map corners,
+  because they could overlap and/or be out of bounds.
 
-Finally, you can define the annotation font, font color, distance from the map
-frame and the precision of the drawn coordinates.
 
 .. _figure_layout_map_coord: