Development of an Integrated Photogrammetric Cad Based Systems (ipcbs) with Emphasis on Real-time Producing of Gis-ready Data

Photogrammetry offers suitable, reliable and accurate methods for gathering data and making 3D digital models, which have vast applications in design and implementation of information systems such as GIS. On the other hand, Computer Aided Design (CAD) systems are used for drawing, editing, and representing 3D geometric models of features. CAD editing functions are used for simplifying data-cleaning tasks before using them in GIS systems and topology building. In the traditional photogrammetric procedures, after drawing raw map by photogrammetric instrument, several man-hours are needed for editing outputs and making them ready to be usable in CAD software or GIS environments. While for saving time and costs, if similar project is implemented by using integrated photogrammetric CAD-based systems, in real-time then map drawing and data editing steps to make it ready for GISs are carried simultaneously. A number of integrated systems have been developed so far, but they don’t support all the data-cleanup tasks at the time of digitizing. In this research, using a comprehensive logical data model and rules, IPCBS (an Integrated Photogrammtric CAD Based System) was designed, developed and implemented at Khaje-Nasir-Toosi University of technology. In order to minimize the editing procedure before using data for CAD purposes or GIS applications, IPCBS eliminates geometric and topologic errors, exactly at the same time of object digitization. Output of system can be directly entered to GIS or automatic cartography systems without any need for further editing process. Using IPCBS, there is no need for replacing traditional systems with completely digital ones and existing semi-analytical stereoplotters and analytical plotters, which are generally familiar for operators, can easily use these facilities. IPCBS can be accommodated by existing standard hardware and operating systems in IRAN and from financial point of view is economic. IPCBS uses event-driven functions to process raw signals, which are received by encoders of plotters (semi-analytical, analytical and digital photogrammetric systems), and then modifies them according to predefined tolerance and its topological cleanup rules and finally converts them to standard format readable for CADs and GISs in real-time (during the digitizing time). These techniques were tested using simulated and real data on Zeiss Planicomp-P33 analytical plotter and MicroStation V5 (embedded CAD software). Output file of IPCBS were successfully tested in several GIS softwares. * Corresponding author.