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Product quality assurance for GIS life-cycle
 Mrinal Kanti Ghose Scientist, Regional Remote Sensing Service Centre ISRO, Dept. of Space, Kharagpur mkghose2000@yahoo.com
Abstract GIS (Geographic Information System) databases are an ever-evolving entity from their humble beginnings as paper maps, through the digital conversion process, to the data maintenance phase. The GIS technology shall comprise of geographic data that is specific and reliable and that represents as closely as possible the spatial world, we live in and neglecting that, the usefulness of the technology is short-lived. To maximise the quality of GIS databases there should exist a well-designed Quality Assurance (QA) plan that is strategically integrated through the entire life cycle of the GIS project. Until quite recently, little attention was paid to the problems caused by error, inaccuracy, and imprecision in spatial data sets. This situation has changed substantially in recent years. It is now generally recognised that error, inaccuracy, and imprecision can “make or break” many types of GIS project. The key point is that even though error can disrupt GIS analyses, there are ways to keep error to a minimum through careful planning and methods for estimating its effects on GIS solutions. Awareness of the problem of error has also had the useful benefit of making GIS practitioners more sensitive to potential limitations of GIS to reach impossibly accurate and precise solutions. The main purpose of this paper is to alert GIS analysts and its potential users to some methods that are especially suited to assessing the Quality of GIS data base and digital maps/ coverage. Attempts are also made to present a set of guidelines that are intended to establish the minimum acceptable level of Quality that should be adhered to by all of the projects and users through out the life-cycle of a GIS. Introduction Today, Geographical Information System has reached a level of Operationalisation and is transitioning from an era of promotion to opportunities for commercial development of the application services. GIS databases are an ever-evolving entity. From their humble beginnings as paper maps, through the digital conversion process, to the data maintenance phase, GIS data never really stops changing. It is now generally recognised that errors, inaccuracies, and imprecision left unchecked can make the results of a GIS analysis almost worthless. Unfortunately, every time a new data set is imported, the GIS also inherits its errors. These may combine and mix with the errors already in the database in unpredictable ways. The key point is that even though error can disrupt GIS analyses, there are ways to keep error to a minimum through careful planning and methods for estimating its effects on GIS solutions. Awareness of the problem of error has also had the useful benefit of making GIS practitioners more sensitive to potential limitations of GIS to reach impossibly accurate and precise solutions. The key to developing and implementing a successful GIS project is a well-designed Quality Assurance (QA) plan that is integrated with both the data conversion and maintenance phases of the GIS project. The fundamentals of Quality Assurance never change; completeness, validity, logical consistency, physical consistency, referential integrity and positional accuracy are the cornerstones of the QA plan. To maximise the quality of GIS databases there should exist a well-designed Quality Assurance plan that is strategically integrated with all facets of the GIS project. Obective of the paper In this paper an attempt has been made to make a systematic study of the various quality parameters of a GIS and their measurements in real life environment. This paper also presents a set of guidelines that are intended to establish the minimum acceptable level of accuracy assessment that should be adhered to by all of the projects and users. The main purpose of this paper is to present an overview of some methods that are especially suited to assessing the Quality of GIS data base and digital maps/ coverage. The issues involved in the development and implementation of an integrated GIS Quality Assurance Plan are also discussed.
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