H. Ebadi, F. Farnood Ahmadi

K.N.Toosi University of Technology



One of the most expensive stages in implementation of a GIS system is preparation of spatial data to be entered into the system. It can be said that about 60-80 percent of the project cost is spent for spatial data preparation. Since the quality and reliability of obtained results from GIS analysis is directly affected by input data, quality of entered data can be known as the most important factor to achieve a successful GIS project

Temporal changes of features as the most important factor in reducing accuracy and reliability of spatial data should be considered carefully to avoid waste of financial resources.

To have an everlasting GIS system, spatial data in GIS must be regularly updated. Recent developments in the field of Geomatics science enable users to utilize different techniques such as photogrammetry, remote sensing, GPS and etc. for fast and systematic spatial data updating. Spatial data updating process consists of three stages:

Detection of changed features

Identification of change type

Revision and updating of features

Since performing each mentioned stages for large amount of spatial data is costly and time consuming, therefore automatic and intelligent approaches to perform these stages can help to save time and cost of the project.

An automatic method for spatial data updating will be more efficient when updating process is performed simultaneously with data collecting stage (on-line updating approach).

Nowadays, most of the developed image processing methods for automatic detection of changed features and identification of change type are based on geometric and radiometric information which are extracted from aerial and satellite images. Some complex and time consuming processes must be performed on images when using these methods. Therefore, they are not effective for on-line updating of spatial data. In many cases, complexity of presented algorithms makes the utilization of these methods impossible for implementation in practical projects which include a variety of features.

Due to the fact that high-speed spatial data collection can be performed by GPS, on-line integration of GPS and GIS systems can be known as a practical and appropriate method for on-line and automatic updating of spatial data.

 In this paper, after reviewing problems and technical requirements for on-line integration of GIS and GPS systems and proposing an algorithm for automatic and intelligent updating of spatial data, the stages of design, implementation and test of GGISIU (GPS and GIS Integrated System for Intelligent Updating) as an on-line integrated GPS and GIS system for automatic updating of spatial data, has been described.