W3C is pleased to receive the Tiling and Layering Module for SVG 1.2 Tiny (SVGTL) Submission from KDDI Corporation.
The Submission proposes a set of extensions to SVG, comprised of four main mechanisms:
Collectively, these features provide a Level of Detail solution suitable for, but not restricted to, vector mapping. Some aspects of this proposal will be of general applicability beyond the mapping use case.
The W3C Scalable Graphics Requirements, published in 1996, list the requirements for a Web-oriented scalable graphics solution. Of these, all are satisfied by SVG except for the Level of Detail requirement.
SVG 1.1 (whose Second Edition is now a Proposed Recommendation) and SVG Tiny 1.2 both define how a single SVG file, representing a map, indicates the projection and map coordinate system used and how this is transformed to graphical coordinates. This Submission extends the idea to allow multiple independent map layers to be georegistered and presented to the user as a composite map.
SVG 1.1 and SVG Tiny 1.2 can reference external vector or raster resources, such as images, but are restricted to downloading an entire resource (although they can clip portions away for display). This Submission extends the idea to allow multiresolution graphics to be declaratively referenced and automatically loaded on demand at the needed resolution in response to user zooming and scrolling. A similar feature, alternate content based on display resolutions , was once proposed for SVG Full 1.2.
Now that SVG is widely implemented, new work is starting on SVG 2. The Tiling and Layering features are candidates for inclusion in SVG 2 to satisfy the Level of Detail requirement.
There has been experimental and commercial implementation of this proposal at various stages of its development, including the SVG Map Toolkit, and an open source implementation based on the WebKit browser engine, which will be announced separately.
This submission is timely, as the SVG WG is in the process of rechartering. In the new charter period, we propose to form a task force dedicated to mapping, including defining use cases and requirements for mapping applications, as well as developing Recommendation-track specifications for use in mapping, taking this Submission as input for one such deliverable. The use cases presented by this Submission will serve as input for future work within a dedicated mapping extension to SVG.$Date: 2011/07/18 16:43:09 $