Have indicator for path normal that can be toggled

[jlstevens]

Closed path can have a meaningful polarity depending on whether they are defined clockwise or anti-clockwise. A similar notion can apply to open paths depending on the direction they are drawn.

This information can be important and it would be useful to have an indicator (typically an arrow) to indicate the 'direction' of the path. Such a visual indicator is something you would probably want to toggle as necessary.

[dharhas]

Not saying we should do this since it will cause issues with using a Polygon as a primary data structure, but for reference I thought i'd explain how the XMS/CMB type suites works.

• Polygons are made of Arcs (i.e. Polylines).
• Arcs have direction and the direction can be reversed. Hence the Polygon might have Arcs with opposing direction. This doesn't fit the standard used for polygons in shapely/geojson etc.
• Each Arc starts and ends at a 'Feature Vertex'.
• Vertices along arcs can also be redistributed keeping the Feature Vertices unchanged.
• Vertices can be promoted/demoted from being a Feature Vertex.

This gives very fine grained control, that allows things like grid generation and setting boundary conditions for models. Unfortunately, it doesn't quite fit into GIS paradigms for representing objects.

[kcpevey]

Still a priority for this phase.