Study Of Three-dimensional Automatic Modeling Techniques Of The Mine Workings

With the development of mining industry, theories and technologies relating to Digital Mine (DM) have increasingly become a focus of attention. As an application branch of GIS in mining industry, aiming at improving operating efficiency and reducing production costs in the term of information production, Mining GIS (MGIS) not only serves as an important component of MD, but also the carrier of information and decision-making. A MGIS of 21st century should be a complex Geographic Information System, which, based on both spatial information and time information, can provide functions, such as dynamic simulation,3D visualization,3D analysis and decision support, for mining industry. It covers more than 3D VR,3D networking, multi-objective analysis and decision making, other functions like exploration assistant, interactive design and plane of mining, real-time management of resources, ecological rehabilitation, and sustainable development of mining industry should also be included. Until nowadays, there is not a single real 3 dimensional MGIS available yet. Most mining software available still remain in the state of CAD assisted 3D modeling or visualization, the capacity of spatial analysis and decision making are more than a little weak. As the channel for ventilation system, water supply system, power supply system, and both mineral and staff transportation, roadway is a complicated geometry network. Construction of 3D roadway model is a critical part of MGIS, and it lays foundation for DM.Based on previous research, existing 3D models for 3D GIS are studied first. In viewing of the characteristics of roadway, facial model is proved to be an appropriate data model for 3D roadway modeling. Then, object-oriented modeling theory and technology are introduced into the roadway modeling process, and a complex roadway system is split into simpler components. A roadway system can be split into single roadways, and a single roadway can be split into roadway segments, then a TIN model is built for the roadway segment with adjacent sections of current roadway segment. Finally, a reverse process is taken out to assemble these components into the 3D roadway system. Meanwhile, their topological relationships are dealt with. In the process of modeling, intensive study is carried out on existing theories and algorithms. Moreover, a TIN construction method suitable for 3D roadway modeling, named "Constrained TIN Construction Method Based on adjacent Sections", is presented. This method is also referred to as "claming ladder" due to it builds TIN in a way like climbing a ladder. After a study on the theories and algorithms for 3D roadway modeling, mid-line and section data are extracted from original CAD data, and the whole modeling process is achieved with standard C++.After building 3D roadway model with previous work, modeling result is written to Shapefiles with GDAL/OGR library in order to facilitate the 3D GIS software, like ArcSecne etc., for debugging. Eventually, further works, such as 3D visualization, spatial query, section topography, are carried out with OpenSenceGraph, an open source 3D software API based on OpenGL.