Morakot Pilouk

Spatial Data Modelling for 3D GIS

This book covers fundamental aspects of spatial data modelling specifically on the aspect of three-dimensional (3D) modelling and structuring. Realisation of true 3D GIS spatial system needs a lot of efforts, and the process is taking place in various research centres and universities in some countries. The development of spatial data modelling for 3D objects is the focus of this book. The book begins with some problems and motivations, the fundamental theories, the implementation, and some applications developed based on the concepts. The book is intended for various geoinformation related professionals like GIS engineers, GIS software developers, photogrammetrists, land surveyors, mapping specialists, researchers, postgraduate students, and lecturers.

Smoothing and Compression of Lines Obtained by Raster-to-Vector Conversion

This paper presents analyses of different methods of post-processing lines that have resulted from the raster-to-vector conversion of black and white line drawing. Special attention was paid to the borders of connected components of maps. These methods are implemented with compression and smoothing algorithms. Smoothing algorithms can enhance accuracy, so using both smoothing and compression algorithms in succession gives a more accurate result than using only a compression algorithm. The paper also shows that a map in vector format may require more memory than a map in raster format. The Appendix contains a detailed description of the new smoothing method (continuous local weighted averaging) suggested by the authors.

Using local deviations of vectorization to enhance the performance of raster-to-vector conversion systems

Abstract. This paper presents a method of quantitatively measuring local vectorization errors that evaluates the deviation of the vectorization of arbitrary (regular and irregular) raster linear objects. This measurement of the deviation does not depend on the thickness of the linear object. One of the most time-consuming procedures of raster-to-vector conversion of large linear drawings is manually verifying the results. Performance of raster-to-vector conversion systems can be enhanced with auto- localization of places that have to be corrected. The local deviations can be used for testing results and automatically showing the parts of resulting curves where deviations are greater than a threshold value and have to be corrected.