عنوان مقاله [English]
One of the main tasks of spatial information systems such as GIS is the aggregation of various data sets and their preparation for communication and analysis in various applications.
The aggregation of data in spatial information systems requires collection of different types of data drawn from multiple sources, which would in turn necessitate complete alignment among these data sets and the similarity of features and phenomena in them. For example, it is possible that spatial information be extracted in several forms and from several sources, that is, the GIS data sources can be maps from land surveying, photogrammetry and remote sensing on different scales or with different resolution or at different times. In addition, there is a risk of data being obtained in ways that are incompatible and different in terms of validity. Some details may also be omitted or not defined. The incompatibility among various data is likely to come from an incompatibility among spatial information of the data recorded, including differences in dimensions (size), shape, composition, position accuracy or orientation.