To improve efficiency and reliability in updating GIS data, it is important to integrate the acuquisition process of GIS data within a GIS environment. In this study, the author proposed a conceptual framwork for the integration of photogrammetric system in a GIS environment. As an example of the integration, the author showed that the efficiecy and reliability in detecting changes in aerial photos is improved by overlaying mask images generated from ‘old’ GIS data on ‘new’ aerial photos through some experiments.
Necessity of an automatic change detection method was emphasized for efficient map revision. The significance and problems of utilizing existing old maps for a change detection system were discussed. A couple of problems in applying basic image understanding techniques to change detection were reviewed, and an attempt was made to solve them with a prototype system developed for use with satellite images and map data. The attempt clarified that every automatic change detection system outputs some errors in its results, and that such systems must have some efficient error inspection functions incorporated well with human inspection capability in order to be practically used. An example of such inspection systems was also presented.
Bangladesh is a flood prone country. The whole of Bangladesh is a huge river basin criss-crossed by three major river systems and their innumerable tributories and distributories. In 1988, there was the worst flood in the living memory of the people, causing awful miseries to vast area of the country, the disruption of roads and communications, the loss of properties, destruction of agricultural land, damages to crops, households and livestocks etc. This present study deals by using NOAA-10 AVHRR imagery with other thematic maps by Geographic Information System (GIS) to estimate flood damage area in 1988 and also calculate some thematic informations inundated by floods.
In these a few years, multi-media has been attracting keen interests in GIS fields, particulary for data browsing and educational applications. Although the real world, where we live and all geographical problems exist, can be observed and recorded by various methods, due to the limitation in capability of computers and also to the traditional concepts for geographical information (maps and statistics), only two types of information (digitized maps with attributes, statistics) have been used in GIS for nearly thirty years. To model and represent real world with more reality, it is important to seek alternative data types and to combine them with existing data types., This paper aims to describe several aspects of multi-media systems in general and to discuss some technological issues common and particular in GIS applications. This paper starts with examination of the definitions of multi-media which is not yet determined. Then the paper discusses media, devices and formats for multi-media recording. A short history of multi-media applications in spatail data handling, including Aspen, Domesday Project and TRINITY is reviewed. Data base structure for multi-media is a hot theoretical issue. Objectoriented approach, formal network data base and themantic network data base are discussed. As a conclusion, the author would like to emphasis that GIS has relied too much on traditional geographic information concept which were made in industrial revolution era in the late eighteenth century. It is important to update conceptts to meet with today's real world and to add more reality to GIS.