# Open-Pit Map: An HD Map Data Model for Open-Pit Mines
## 2 Application Scenario of HD Maps for Open-Pit Mines  
### Research Status of HD maps  
HD maps include a data model and storage file format, with the data models constituting the core [11]. The data model is the abstract and digital expression of the physical elements in the real scene, and the data logical structure that accurately reflects the scene elements and the road environment. The data model of HD maps usually includes elements (objects), attributes and relationships, classification and organization of data, coding of data, geometric and topological representation relations, and production and application expansion oriented toward the scenario requirements [12].  
1. \"NDS (Open Lane Model)\". NDS is a navigation electronic map data storage standard based on an embedded database, which is oriented toward vehicle navigation and supports incremental updates [13]. It divides the content of map data into six logical functional structure units (building blocks): road, lane, name, basic map display, area of interest, and traffic information. The Open Lane Model 1.0 released by NDS is an independent release of the standard lane modeling, lane connection, lane identification, lane type attributes, and other elements to further promote the application of navigation maps in autonomous driving.
2. \"Lanelets\". Lanelets is an open source HD map format for autonomous driving [14,15]. A road network in Lanelets maps is made up of lanes, roads, and intersections. Each lane segment consists of left and right borders, which are themselves polylines. Interconnecting lanes (lanelets) can be used to describe the driving area of an autonomous vehicle, which can satisfy the path planning and traffic rule compliance of an autonomous vehicle. Lanelet2 describes the frame of the map in more detail. The basic elements are divided into two layers: the physical layer, which consists of real, observable elements, including strings of points and lines and the relationship layer, including traffic rules and applicable lanes.  
3. \"OpenDRIVE\". OpenDRIVE is an open data standard and a description of a static road network, which is commonly used in driving simulation and traffic simulation [16]. It uses nodes and elements to organize various types of information in the road and adds detailed attributes. For example, roads, lanes, links, traffic lights, and intersections are used to build road traffic networks.
4. \"Apollo OpenDRIVE\". Baidu's open source project, Apollo, has made some improvements to the OpenDRIVE format based on its own application scenarios and practical experience [17]. For example, Apollo Opendrive uses point sequences composed of absolute coordinate points to describe the geometric shape of elements, such as the description of road boundaries, which can describe complex lane shapes more efficiently and is more common in data expression.  
Various international data standards [18] were extensively referenced when establishing a high-definition data model for an open-pit mine's topographic map, the above three most widely used standards were selected for comparison, as shown in Table 1. The NDS format is oriented toward vehicle navigation applications and has a complex and rigorous storage format, which is difficult to apply directly. The Lanelets map format relies too much on small lanes (lanelets) and the topology of road networks is complex. Lanes in OpenDRIVE are created by lateral offset relative to the road reference line, which is complicated in a scenario with many lanes and variations. However, in open-pit mines, there is basically no multi-lane changing road in the same direction, and the OpenDRIVE data standard is the most widely used in Chinese autonomous driving technology companies. Therefore, the basic elements and formats involved in creating the road network in OpenDRIVE and Apollo are referenced and given a new meaning in conjunction with the open-pit scenario.