Investigating the effect of cartographic properties on updating cadastral maps

Abstract

Cadastral maps are the main documents of ownership and plots of land, as it contribute to preserving the property rights of individuals and institutions. It indicates the size and shape of each parcel and reveals geographic relationships that affect property value. The Iraqi cadastral maps are in old coordinate system AL-nahrwan 1934 and lambert conformal conic projection. Therefore these maps are old and unfit for use. The main objective of this paper is to investigate the effect of cartographic properties on updating cadastral maps. This depends on studying the effect of conversion the projection and the datum of the cadastral maps of the study area from (datum: nahrwan34, projection: lambert conformal conic) to the (datum WGS84, projection: UTM). The results indicated that the distortions are very small in small areas and distance, but it increases with increasing areas and distances. While, there is no distortion in directions. The Affine (2D) and Molodensky (3D) transformations were used in datum transformation. The total root mean square error (TRMSE) of affine transformation was ±0.895m, while it was±0.651m for Molodensky results. Therefore, the Molodensky method was used to transform the datum for all cadastral maps.