Quadtree Coding Research Articles

Interactive editing of cartographic raster images

A system for manipulations of binary images is presented. They are generated by segmentation of grey-scale images and stored in a runlength- or quad-tree code. Their standard-size is about 50 million pixels. Besides the raster-to-vector conversion, one main component is a raster-based interactive graphic editor. Handling such large amounts of data fast enough for interactive work on a normal computer (e.g. DEC-VAX) requires specific software solutions. Therefore, a program architecture has been designed to support port asynchronous work on the screen and to update the data on disk. Furthermore, algorithms take advantage of the quad-tree coding and the fact, that the largest part of a cartographic raster image is background. The software is linked to a vector-based graphic information system to meet the requirements of cartographic applications.