ERROR PROPAGATION MODELING IN GIS POLYGON OVERLAY

A spatial error may refer to the difference between a measured value and the “true ” value or the estimated uncertainty with respect to a given observation or set of observations which is the error contained in the coordinate values of points, lines and volumes. This paper focuses on developing a methodology for error handling and error propagation modeling in spatial database with GIS. The main target of this study is error propagation on vector polygon overlay in a GIS. An error model was developed to examine errors from its component layers. Error simulations on intersection points proved an important fact that overlay error can be calculated from its components. This error is an average of the component errors. Sliver error was also analyzed and simulated to come up with a solution for solving this common error in overlaying polygons. It is recommended to split-and- merge slivers, not to delete nor combine. In most cases, the splitting line can be drawn to follow proportional weights to the errors in two boundary lines from their original polygons