Primary features are edges and lines. Relation ships between edges can easily be established in terms of distance. Relationships between lines csn be established in terms of angles. With a set of 3 edges relationship angles for edges can be established.
Also if an edge is perpendicular to a line within the bounds of the line, the perpendicular intersection with the line forms a new type of feature with an absolute position just like an edge has... perhaps slightly less accurate
Primary features are edges and lines. Relation ships between edges can easily be established in terms of distance. Relationships between lines csn be established in terms of angles. With a set of 3 edges relationship angles for edges can be established.
Also if an edge is perpendicular to a line within the bounds of the line, the perpendicular intersection with the line forms a new type of feature with an absolute position just like an edge has... perhaps slightly less accurate