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The cutting edge 'Geoinformation' revolution

Potential developments
For hundreds of years, traditional surveying has been constrained with required line of sight, but after evolution of GPS, one does not need to maintain clear line of sight. GPS offers all weather surveying with a clear view to the sky without need to traverse across intervening land or around obstacles. Developments in GPS occur at an unbelievably rapid speed, which can be appreciated by looking at the speed of GPS innovation. For example, observation time has been shortened from 5 hours to 5 minutes, and most notably the accuracy level has improved from couple of centimetres over a few kilometres to a couple of centimetres over 10,000 kilometres. After removal of SA, single point positioning accuracy of 10 meters can be obtained (GPS World, 2001).

However, GPS technology cannot be seen as a panacea, its potential can be realised while integrating it with other geoinformation and communication technologies for cost-effective solutions. There are several ways to consider integration of GPS into GIS environments, which can be categorised as data focused, position-focused and technology-focused integration (Harrington, 1999). The following discussion provides rationale for integrating GPS with other geoinformation technologies.

1. Surveying
   The integration of GPS, GIS and remote sensing offers efficient solution to large-scale surveying. Patel (2002) had articulated a case for integration of theses technologies, which provides opportunities for economic geo-referenced spatial data augmentation techniques. In particular, the use of GPS in land surveying proved a great efficiency and accelerated data acquisition with required accuracy for topographic and cadastral plans. For example, the use of GPS in CAD environment in Morocco suggests considerable time and resource savings to develop cadastral and topographic maps with relative accuracy of 10cm (Elayachi et al., 2001).
   
   
2. Geospatial data acquisition
   Processing and analysis of spatial information/data presupposes availability of positional data, however most local governments in developing countries do not have adequate spatial data and whatever data is available is outdated. The ability of GIS performance to carry out spatial analysis crucially depends upon quality of data available. This indicates the need for resurvey at a regular interval to capture short- and long-term variations in the field in order to keep the data in real-time. GPS is increasingly used as a tool to input data for GIS, particularly for precise positioning of geospatial data and collection of data in the field. Remote sensing images have been used as a real-time spatial data source, however they require corrections before using in a GIS environment. The process of correcting remote sensing imagery, georeferencing, requires accurate ground control points. Cook and Pinder (1996) and kardoulas et al. (1996) reported that rectification of Landsat TM, SPOT Multi spectral and Panchromatic images became easier by using GPS that eliminate time involved in establishing ground control points. Gao (2001) also preferred non-differential GPS technique for image rectification using ground control points.
   
   
3. Maintenance and updating enterprise database
   Managing decay in GIS data due to urban sprawl and regeneration is one of the most challenging tasks in front of local authorities. GPS-based tools for GIS data maintenance have the potential to substantially reduce the cost of reversing decay in GIS database and keep it real-time. In response to continuous process of urbanisation, resurveying is required at regular interval to acquire field data, which needs modification of thousands of features into an enterprise wide database. The innovative hand held GPS receivers with integrated wireless communication technology enable collection and management of large-scale geospatial data using the Internet/intranet. The advantage of wireless modem helps field crew to send new or updated data to a central data processing unit, where quality assurance is carried-out. This helps in rapid turn-around for data that may need to be re-acquired while crew is still in the field. The WWW based local area augmentation system can continuously receive satellite data and supply field data for real-time applications. The real-time map display, editing, post-processing, and conversion are becoming better integrated, more functional and easier to use with pen-based ruggedised field computers.