General Information
The OGC standard ‘Land and Infrastructure Conceptual Model Standard’ (LandInfra) defines concepts for providing and understanding information about land and civil engineering infrastructure (Gruler et al. 2016). These concepts are formally defined using UML diagrams. The standard covers various subject areas defined by so called requirement classes. The most relevant in terms of street modelling are Alignment and Road. An Alignment is defined as a positioning element which provides a linear referencing system for locating physical elements. It can be defined in several ways such as horizontal, vertical or 3D alignment. For roads, there is typically an Alignment for the centreline. For dual carriageway roads, separate alignments should be realised, however they may also share a reference horizontal alignment at the approximate centre of the entire road. Based on a Linear Referencing Method (LRM) locations along the Alignment can be defined as linearly referenced locations. DistanceAlong and offsetLateralDistance values shall be measured in the horizontal plane and ignore any vertical displacement if Alignment is used as a linear element. OffsetVerticalDistance values can be considered. The class Road contains multiple alternatives for representing a road design such as RoadElements, 3DStringLines (~ profile views), 2D CrossSections and ‘3D surfaces and layers’. Road elements can include many different types such as pavement, sidewalk or curb defined by an attribute called RoadElementType. Multiple road elements can be grouped together as RoadElementSet. RoadElements can be physically located optionally by a spatial representation or a linearly referenced location. Any particular point in a cross section can be represented by a 3DStringLine. The surface of a road can be represented by a triangulated irregular network (TIN). This is not limited to the top surface of the constructed road but can also be used to model subsurface information.