Add a small note on the heights of the boundary.

Signed-off-by: Thomas Bleher <thomas.tb.bleher@bmw.de>

Author: tbleher

osi_logicallane.proto

@@ -9,7 +9,7 @@ package osi3;
 //
 // \brief Boundary line of a LogicalLane
 //
-// Similar to a LaneBoundary, but with a reference and ST positions.
+// Similar to a LaneBoundary, but with a reference line and ST positions.
 //
 // A logical lane boundary describes the boundary between two logical lanes. As
 // such, there will always be exactly one logical lane boundary between two
@@ -23,6 +23,11 @@ package osi3;
 // marking), then the single LogicalLaneBoundary describing the boundary between
 // two logical lanes should be between the physical boundaries.
 //
+// A logical lane boundary consists of a list of \link LogicalBoundaryPoint
+// LogicalBoundaryPoints\endlink. Each point has a XYZ and an ST coordinate.
+// The XYZ coordinates describe the position and height of the boundary in the
+// world.
+//
 // Notes on design decisions:
 // - The LogicalLaneBoundary has ST coordinates, and is thus a separate type
 //   from LaneBoundary.
@@ -79,7 +84,7 @@ message LogicalLaneBoundary
     // Approximation error green line.
     //
     // The Z error (difference in Z height between #boundary_line and the
-    // "real" line) must not exceed 2cm. This is a stricter requirements than
+    // "real" line) must not exceed 2cm. This is a stricter requirement than
     // for errors in the XY plane, because Z differences between lanes
     // influence driving very much.
     //