Journal of Surveying Engineering

Geomatics firms are under competitive pressure to bring their products to market more quickly. Increasingly, production contracts involve multiparticipant, distributed project teams. This paper discusses the potential to apply computer-supported cooperative work concepts and groupware tools to multiparticipant, distributed geomatics projects. Groupware tools are categorized into an application-based computer-supported cooperative work framework. Current collaboration models, including proprietary and Internet-based models (intranets and extranets), are discussed in terms of their relative strengths and weaknesses. An extranet-based collaboration model is suggested as an appropriate model for current multiparticipant, distributed geomatics projects. Design considerations for an extranet-based collaboration model are given and the shortcomings of such a model are reviewed. The paper concludes by pointing to future research, which will include incorporating new and evolving groupware and collaborative strategies, and performance testing of a collaborative workspace in specific production scenarios.

The quality of digitized spatial databases directly affects many mapping applications and decision-making processes in geographic information systems (GIS). Because all information in GIS is, to some extent, related to spatial data, spatial accuracy plays a very important role. A large number of features in digitized databases contain rectangular and straight-line segment components. This is especially true for urban GIS databases, where rectangles and straight lines are the most common basic features. Automatic validation of such digitized components and features is part of the approach toward applying a quality control process before the databases are used in applications. This paper introduces a least squares adjustment (LSA) method for validating digitized rectangular and straight-line features. The method can be seamlessly implemented in digitizing software so that the digitized features can be automatically checked and corrected, and the spatial quality is enhanced. In addition, the overall digitizing quality indicator estimated from the validation procedure can be used to represent the spatial quality of the digitized features, although it is only an internal or relative quality measure. Such a quality measure is also critical to the uncertainty modeling in GIS. The results of an experiment using this validation method are given.

A seven-parameter datum transformation model is constructed for transformations between the World Geodetic System (WGS84) datum and the Hong Kong 1980 local datum. The solution is tailored by biasing the height information in the WGS84 system to obtain better agreement with the Hong Kong datum height values. The influence of the tailoring process on the accuracy of the model parameters is assessed.

In planning and design of sewer networks, most decisions are spatially dependent because of the right-of-way considerations and the desire to have flow by gravity. The geographic information system- (GIS-) based approach takes advantage of the spatial analysis capability of GIS in combination with a sewer design program to develop an integrated procedure for the design of sewer systems. The program that was developed uses the user specified manholes' locations to generate the sewer network. The GIS is used to analyze the area's topography, surface features, and street network to delineate subwatersheds, to locate pump stations, and to determine the path for the force main. The program was successfully demonstrated for two areas in the town of Blacksburg, Va. In comparison with a traditionally designed path for the force main, the developed approach results in a better design. It also was possible to design a complete sewer network with minimal human intervention.