Special Feature – Spatial Data Infrastructures

Rajabifard, A., Binns, A. & Williamson, I. (2006) Virtual Australia: Developing an Enabling Platform to Improve Opportunities in the Spatial Information Industry, Journal of Spatial Science, Vol. 51, No. 1. 

Wallace, J., Williamson, I. P., Rajabifard, A., & Bennett, R. (2006) Spatial Information Opportunities for Government, Journal of Spatial Science, Vol. 51, No. 1. 

Tomko, M., & Winter, S. (2006) Recursive Construction of Granular Route Directions, Journal of Spatial Science, Vol. 51, No. 1. 

Abstracts

Refereed Papers

Abstract

Testing Theory and the Minimal Detectable Bias

K. W. Blesch

P.O.BOX 448,

8200 AK, Lelystad

The Netherlands

kblesch@planet.nl

Abstract

Quality control is described by internal and external reliability according to the Delft  philosophy.  Internal reliability describes the ability to find biases in observational data and is represented accordingly by the Minimal Detectable Bias (MDB). MDB is the size of a model error that can just be detected with a certain probability, using the appropriate test  statistic.  External reliability describes the effect of not detected errors on the final results of the estimated parameters in an adjustment computation. In practical computations, the size of these undetected errors is set equal to the MDB. In this paper a review is given of the Delft approach of statistical testing observations and the MDB.

It is proved that the developed test statistics, in fact, project the sum of all occurred model errors on the direction defined by the alternative hypothesis and, consequently, the MDB thus does not say anything about the minimal bias which can be detected by testing the observations according to the theory.

Height systems and vertical datums: a review in the Australian context

W. E. Featherstone

M. Kuhn

Western Australian Centre for Geodesy

Curtin University of Technology

GPO Box U1987, Perth, WA 6845

Australia

W.Featherstone@curtin.edu.au

Abstract

This paper reviews (without equations) the various definitions of height systems and vertical geodetic datum surfaces, together with their practical realisation for users in Australia.  Excluding geopotential numbers, a height system is a one-dimensional coordinate system used to express the metric distance (height) of a point from some reference surface.  Its definition varies according to the reference surface chosen and the path along which the height is measured.  A vertical geodetic datum is the practical realisation of a height system and its reference surface for users, nominally tied to mean sea level.  In Australia, the normal-orthometric height system is used, which is embedded in the Australian Height Datum (AHD).  The AHD was realised by the adjustment of ~195,000 km of spirit-levelling observations fixed to limited-term observations of mean sea level at multiple tide-gauges.  The paper ends by giving some explanation of the problems with the AHD and of the differences between the AHD and the national geoid model, pointing out that it is preferable to recompute the AHD.

Spatio-Temporal Data Management Using Object Lifecycles

A Case Study of the Australian Capital Territory Spatial Data Management System

K. Stock

ACT Planning and Land Authority

16 Challis Street

Dickson ACT 2602

kmstock@comcen.com.au

Abstract

The representation of time in spatial information systems allows historical data to be maintained and analysed, but increases system complexity.  While many early methods for handling spatio-temporality are limited or inefficient, more recent methods are expressive but complex.

The object lifecycles method represents temporality using discrete stages in an object’s life, focuses on the aspects of spatio-temporality that are relevant to a specific land administration domain and is therefore simpler than the spatio-temporal methods that are designed to handle all scenarios.  The method has been successfully applied in a production environment: the ACT Spatial Data Management System.

Abstract

The role that the development of Spatial Data Infrastructure initiatives is playing within the modern world is changing. Initially SDIs were implemented as a mechanism to facilitate access and sharing of spatial data hosted in distributed GISs. Users however now require precise spatial information in real time about real world objects and the ability to develop and implement cross-jurisdictional and inter-agency solutions to priorities such as emergency management, natural resource management, water rights, and animal, pest and disease control. In order to achieve this, the concept of an SDI is moving to a new business paradigm, where SDI is emerging as a ‘virtual jurisdiction’ or ‘virtual enterprise’ to promote the partnership of spatial information organisations (public/private) to provide access to a wider scope of data and services, of size and complexity that is beyond their individual capacity. The development of such an SDI requires an enabling platform to support the chaining of services across participating organisations.

Spatial Information Opportunities for Government

J. Wallace

I. P. Williamson

A. Rajabifard

R. Bennett

Centre for Spatial Data Infrastructures and Land Administration

Department of Geomatics, The University of Melbourne,

http://www.geom.unimelb.edu.au/people/ipw.html

j.wallace@unimelb.edu.au

Abstract

Land administration systems (LAS) are now challenged by new technologies and radically different demands for land information for modern governments.  Spatial information is good enough to support spatial identification and location enablement applications available in every significant type of software (word processing, spread sheets, professional applications, Web systems, GIS and databases). A place on earth can be defined with precision on the ground and in computers.  Digital data can be attached to a location as never before.  With appropriate computer facilities and the underpinning interpretative information layers which translate computer language into understandable descriptions of places, governments can potentially identify “where” their policies are happening. A nation’s ability to reap the benefits of the spatial enablement of information requires the highest level input from its government and private sectors.

These challenges are discussed in the context of developing a vision of iLand, a concept of spatially enabled information for modern government.  This article sets this vision in the history of land administration, and the growing reliance on a new kind of information about land and its attributes that is relative and aspatial in regulation of activities and taxation.

You-Are-Here Maps in Emergencies –

The Danger of Getting Lost

A. Klippel

Cooperative Research Centre for Spatial Information

Department of Geomatics

University of Melbourne, Australia

aklippel@unimelb.edu.au

C. Freksa

Transregional Collaborative Research Center

SFB/TR 8 Spatial Cognition
Universität Bremen, Germany

S. Winter

Department of Geomatics

University of Melbourne, Australia

Abstract

This article evaluates criteria for the design of so-called You-Are-Here (YAH) maps, i.e. maps that explicitly indicate the position of the map reader. Established design criteria are rendered more precise and applied in an exemplary assessment of three YAH maps as they can be found in public buildings as part of a general emergency scheme. The clarification of the YAH map terminology is necessary to allow for assessing the quality of existing YAH maps and consolidates the basis of rule-based generation of location-aware information services. Possibilities for further empirical evaluation of YAH maps are discussed and the role of location-aware technology is considered for smart mobile systems and smart environments.

  Professional Papers

 The Korrong Project - Semi-submersible Imaging for Environmental Mapping in Shallow Water

J.H.J. Leach

Department of Geomatics

University of Melbourne

Parkville

Victoria 3052

leach@unimelb.edu.au

Abstract

In 1996 a unique vessel with an imaging pod that descends beneath the surface was developed to image the marine environment. The system is used to take photographs, make video transects, and to allow human observation. Water clarity normally limits the vessel’s operation to less than six metres depth.  Video transects are the most common usage of the vessel. Using the vessel, long distances are covered by video transect rapidly and cost effectively. Frames from these transects can be used to create mosaics or stereo pairs. Designed as a research tool, the vessel has proven itself a valuable operational asset in monitoring the shallow marine environment and demonstrated the technique of semi-submersible imagery.