International Workshop on Mobile Mapping Technology

The International Workshop on Mobile Mapping Technology was successfully held in Bangkok, Thailand, April 21-23, 1999. It was co-organized by ISPRS WG II/1 Real-time Mapping Technologies, IAG SC4/WG1 Mobile Multi-Sensor Systems, FIG C5/WG3 Real-time Precise Mapping, ISPRS WG V/1 Close-Range Imaging and Metrology, ISPRS IC WG V/III Image Sequence Analysis. The sponsoring organizations included International Society for Photogrammetry and Remote Sensing (ISPRS), Asian Institute of Technology (AIT), National Research Council of Thailand (NRCT), International Association of Geodesy (IAG), International Federation of Surveyors (FIG), Association for Real-time Imaging and Dynamic Analysis (ARIDA), and Japan Association of Remote Sensing (JARS).

The workshop, held at Maruay Garden Hotel in Bangkok, provided a stimulating casual environment to promote scientific presentations, interactive discussions, and information exchange. It brought together 190 participants from 17 countries, who are specialists, engineers, users and those interested in mobile mapping technology, kinematic real-time positioning, sensor integration and calibration, feature extraction and 3-D data acquisition. 42 oral presentations in 12 sessions and 18 posters reported most recent R&D and application achievements of mobile mapping. Among them were 2 oral sessions and 2 poster sessions organized by ARIDA and JARS. In addition, a visit to AIT ’s Asian Center for Research on Remote Sensing (ACRoRS) was organized as a social event. Most participants also enjoyed the visit to Old Ruins and Sleeping Buddha in Ayuttaya, Bangkok.

Keynote speaker, Prof. A. Gruen, made a very informative talk "Mobile & Real-time Mapping" at the opening session. Ron Li delivered a speech "Large-scale Mapping of Landing Sites on Mars and Rover Localization – An Application of Mobile Mapping?" which presented an on-going joint JPL/OSU project on Mars rover localization.

The well-attended workshop also offered technical papers covering a full spectrum of mobile mapping technology. The following highlights some of the papers presented.

A paper from Hong Kong Polytechnical University reported difficulties of kinematic positioning in applications using GPS in densely structured urban areas. Most systems reported by other speakers approach the kinematic positioning by integrating GPS with Initial Navigation System (INS). Such systems are able to maintain positions even when the GPS measurements are not available within a short period. Better estimates can be made until GPS signals return. Furthermore, the combination of forward and reverse Kalman filter estimates enhances the precision of the platform location over the period.

Sensor integration and calibration have become an important part of mobile mapping technology. Calibration aspects of a rapid route mapping system developed in University of Melbourne, Australia was presented. A paper from University of East London discussed the details of calibrating a zoom lens CCD imaging unit in a motorized videotheodolite system. A concept of integrating multi-platform and multi-sensor data was introduced in a presentation from OSU. University of Stuttgart discussed an approach to assist positioning using spatial databases.

Automatic object extraction and recognition from mobile mapping data is understood to be a critical issue. The Calgary team summarized their efforts in the development of automatic approaches to acquisition and processing of mobile mapping images. The OSU team presented results of feature extraction from mobile mapping imagery sequences using geometric constraints and 3-D object recognition using neural networks. Royal Institute of Technology, Sweden, reported automatic road width measurements in a color image sequence acquired by a mobile mapping system.

There is a growing number of mobile mapping systems developed in different parts of the world, including land based and airborne systems. Some are developed for special purpose, for example, for railway survey by Royal Melbourne Institute of Technology, Australia. Wuhan Technical University of Surveying and Mapping, China newly developed an economic mobile mapping system without INS component. However, map matching is tested to improve image orientation. Delft University of Technology presented a method for fast determination of parametric house models from dense airborne laserscanner data that have an average point density of approximately five points per square meter. A more sophisticated system developed at the Ohio State University has been improved to integrate LIDAR data with direct digital GPS/INS oriented imagery for the surface extraction purpose. The mobile mapping system developed by the University of Calgary has now additional functions that use expert knowledge in calibration, planning, surveying and post-mission quality control.

Building a mobile mapping system by integrating off-the-shelf hardware and software components is getting easier, but it requires significant courage, investment and efforts. We have seen development activities by many universities and companies on almost all continents in recent years. Land-based systems have demonstrated the power promised at the early time of the development, for example in road and railway survey, utility survey and others. The takeover of the part of such traditional surveying markets is believed to be only a start. Meanwhile, the very same concept has been transferred to airborne and satellite-borne platforms where positional and orientational sensors are integrated with imaging sensors to approach real-time mapping that is not restricted to where only land vehicles can reach. The "dream" is to achieve the same level of ground position accuracy as traditional aerial triangulation. Of course, an integration of the sensor-based orientation data with aerial triangulation would provide much better results. We trust that with the rapid development in mobile mapping, automatic triangulation, and automatic feature/image matching, real-time systems will be a reality in the near future.

Today, mobile mapping is supported by a series of advanced technologies, including navigation sensors of GPS and INS, imaging sensors of high-resolution CCD, SAR, multispactral and hyperspectral sensors, computers and high intelligent processing/automation algorithms. A question we may want to ask ourselves is "have the current mobile mapping systems reached full potential?" The answer is a definite NO. We still see that mobile mapping takes only a small percentage of the overall surveying market where it ought to do a better job. Four aspects need our attentions: a) prices of mobile mapping systems are high, partly contributed by high cost components such as INS and very large CCD chips, b) better tools for efficient and automatic extraction of useful information from massive mobile mapping data are needed, c) accuracy should be increased for applications where higher accuracy is desirable, and d) efforts should be made to make the spatial data community more aware of the existence and potential of the technology. This workshop served as a forum for researchers, developers and users of mobile mapping systems to summarize the achievements, find out the current problems, and map out the future development. The 410 page proceedings of International Workshop on Mobile Mapping Technology, edited by R. Li and S. Murai (ISSN 0256-1840), can be ordered from RICS Books, Surveyor Court, Westwood Way, Coventry CV4 8JE, United Kingdom, Fax: +44-171-334-3800.

The FIG C5 actively participated in the symposium by having two members in the organizing committee (Dr. Naser El-Sheimy and Prof. Jean-Marie Becker) and 4 members as chairpersons of four different sessions (Dr. Naser El-Sheimy, Prof. Jean-Marie Becker, Prof. Michael Chapman, and Dr. Vincent Tao). During the panel discussion, FIG C5 received support to organize the 3^rd Mobile mapping Technology Conference in Luxur, Egypt on 4-6 January 2001. The technical and social program for the conference is currently being developed. Considerable effort will be expended in order to attract a number of working groups from different international organizations.

Finally, on behalf of the FIG C5, many thanks Dr. Ron Li and Prof. Shunji Mauri for the work that went into the preparation for this meeting and for the success in attracting all these working groups from different professional and scientific organizations.

The next International Conference on Mobile Mapping Technology will be held in Luxor, Egypt, January 4-6, 2001. For further information please contact Dr. Naser El-Sheimy, Department of Geomatics Engineering, The University of Calgary, 2500 University Dr. N.W., Calgary, Alberta, Canada T2N 1N4, Tel : (403) 220 7587, Fax : (403) 284 1980, E-mail: naser@ensu.ucalgary.ca.