Direct Georeferencing
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The 4th International Symposium on Mobile Mapping Technology (MMT 2004) was held on March 29-31, 2004 in Kunming, China. This was the premier event sponsored jointly by the working groups from ISPRS, FIG and IAG, including ISPRS Commision I, WG II/1, WG II/2, WG IV/2 and WG V/5, FIG WG 5.3 and IAG WG SC4.1. For further details, see http://www.geoict.net/mmt2003/index.htm
MMT2004 offered a forum for decision makers, researchers, developers, system integrators, and commercial system vendors in the mobile mapping community. The advancement of Mobile Mapping technology has contributed to many aspects in Geomatics, surveying, and mapping. This symposium reflected the latest developments in mobile mapping technology, ranging from algorithm research to system development, from land-based to airborne systems, from direct georeferencing to sensor integration, from mobile data collection to dynamic GIS management, and to mobile sensor networks. The conference covered the following themes:
Mobile Mapping Technology:
Where are we Heading?
Mobile mapping refers to a new means of mapping based on a dynamic
mobile platform such as a vehicle or an aircraft. Nevertheless,
the term “mobile mapping” has never been clearly defined due
to
the rapid development in this field. It is understood that mapping is
essentially mobile, for instance, aerial photogrammetry. So, what
makes mobile mapping unique?
The research on mobile mapping dates back to late 1980s in North America. It was mainly driven by the need for highway infrastructure mapping and transportation corridor inventory. Video cameras, along with navigation and positioning sensors, for example, GPS and inertial sensors, were integrated and mounted on a mobile vehicle for mapping purposes. Objects can be measured and mapped from images that are directly georeferenced by the navigation and positioning sensors. In early days, the research community had used various terms to characterize this new technology. Terms such as “mobile surveying,” “dynamic mapping,” and others appeared in many publications. In 1997, the first Mobile Mapping Symposium was held at the Center for Mapping of The Ohio State University. “Mobile Mapping” then became a popularly accepted term by both the research and development communities.
With the development of direct-georeferencing and multi-sensor integration, the technology has matured to the operational level with a number of commercial systems developed and in operation. Currently, there are many private companies who offer commercial mobile system development, integration and services. One of those is Leador Spatial Ltd., which exhibited their latest mobile mapping system at the conference venue.
There has been an impressive development in airborne digital camera systems, lidar and IfSAR mapping systems. It is believed that mobile mapping would be a nice technological framework that covers this fast growing technology driven by the integration of directgeoreferencing, multi-sensor integration, data fusion, information extraction, and mobile data management and services. Although airborne lidar and IfSAR mapping was one of the main themes covered by this Symposium, there were also technical sessions scheduled for this area. It is expected that the joint organization with ISPRS WGs on lidar and IfSAR mapping can be arranged in the future to strengthen the framework development for mobile mapping.
From the data acquisition viewpoint, it is clear that direct georeferencing has contributed significantly to the development of mobile mapping systems. The MMT symposium series has built a strong vehicle linking researchers and developers from the ISPRS, FIG and IAG communities. One of the hot issues discussed in this conference was whether the direct-georeferencing technology has matured. The user community believes that the airborne directgeoreferencing systems are much more advanced than those of landbased systems in terms of technical reliability and maturity. Frequent GPS signal blockage has made the GPS/INS integration much more difficult in the urban environment for land-based mobile mapping applications.
The conference also addressed the key barriers relating to commercial and technical development of land-based systems. Compared to aerial mapping, which has been practiced for years now, land-based mapping systems have not reached market acceptance. The possible reasons can be summarized as:
(a) the technology is primarily developed for transportation applications but not for the conventional mapping community. It would take longer for market penetration. It also takes time for technology education of the community which is not familiar with the mapping technology;
(b) lack of mapping standards may prevent the adoption for largescale applications;
(c) the performance and accuracy of mobile mapping systems vary greatly depending on the system configuration;
(d) the cost for system building and maintenance can be expensive for early adopters. However, there have been increasing demands for land-based mobile mapping for transportation and highway mapping applications. Some vendors offer road image services or, a pay-per-click model, to attract customers and to lower the market entry costs for this technology. Instead of owning a system or a software package, the customer may alternatively purchase the road image data collected by the mobile mapping company and only pay for the objects collected from images (pay per click).
Compared to previous MMT symposiums, there were many more papers addressing mobile mapping data management and services, as well as mobile GIS. In fact, mobile mapping is used often in Asian communities, with a focus on mobile field data collection or mobile GIS. Clearly, with the increasing technical maturity of mobile mapping systems, mobile mapping services or valueadded services by making use of the collected data could become one of more important components in the entire food chain. One can envision that the future of mobile mapping systems is mobile mapping services.
The next symposium on Mobile Mapping Technology will be held in Padua, Italy, hosted by CIRGEO (Interdepartmental Research Center for Geomatics), University of Padua, Italy.
Authors
Dr. Vincent Tao, Canada Research Chair
York University, Canada
Dr. Mohamed M.R. Mostafa, Chief Technical
Authority-Airborne Systems
Applanix Corporation, Canada
Edited by Dr. Mohamed M.R. Mostafa, Applanix Corporation.
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