Seamless map-layer and its seamless rules on distributed heterogeneous spatial data

The new generation of distributed GIS makes the management of distributed heterogeneous spatial data goes on a seamless integrated way, various kinds of spatial data centers appear. However, these data centers only integrate distributed heterogeneous spatial data but have a far way to achieve seamless application. Considering various kinds of physical gaps, this paper proposed the concept of seamless map-layer and defined 10 rules of seamless treatment to clear a variety of gaps existing at the same time. These seamless rules include spatial frame of reference, boundary smooth rules, property rules, multi-scale rules, and metadata rules. Then seamless cleaning process has been elaborated. Finally, in the prototype system which we have developed, heterogeneous land use data have been successfully cleaned and built as a seamless map-layer. Test improves the correctness, effectiveness and feasibility of such a seamless method. On the truly seamless map-layer, advanced seamless spatial application can be carried out.