Thank you very much for comments on many sympathies.
Still I do not fully understand, but by reading the source code of the site you showed in addition to the spec sheet, I interpreted that MapML has the following three features.
- It has a mechanism for set a map panel (canvas) with a UI for displaying a map on a web browser : < map> element
- It has a mechanism to express one “map” content. It combines layers as resources on the Web such as raster tiles and vector data to form a set of layers. : < map> element and < layer-> element
- It has independent markup language that mainly serializes vector data (geometry such as point, lineString, polygon) by microXML : document format with < mapml> document root element
Please note, as SVGMap that I design treats them separately, I think that the first and second features are another thing as my viewpoint.
First, about the third feature, the description language with < mapml> root element. I felt its similarity with geoJson, classical GML, KML. I felt I needed to know the motive for you to design this. There are a couple of my imagination, including elimination of the complexity of GML by microXML, pursuit of higher consistency with html.
Here, I expected SVG to probably have the same purpose as these. For that reason I have been designing SVG with geographic information extensions applied as geographic information data format. The reason I chose SVG is basically because I wanted to merge the geographic information with the data format of other web content. SVG has a common concept with many geometries of geographic information. However, it goes without saying that standardization of SVG has a history of suffering.
Here, I also made SVG have its role in SVGMap. SVG has a function to embed web contents based on a painter model such as image element forignObject element and iframe element (SVG 2.0). There are also iframe elements and img elements in html, and it is possible to synthesize layers by manipulating CSS. Therefore, I thought that I needed to know the motivation you designed the < layer-> element.
Here, I think that functions such as zooming, panning, and layer control, which are bound to the < map> element, are not only useful for geo maps. For example, the zoom pan function is also widely used for viewing Ultra High Resolution Graphics (such as Deep zoom: https://en.wikipedia.org/wiki/Deep_Zoom, https://openseadragon.github.io/) and vector graphics data. And the layer control function is widely used in the technical drawing field. Therefore, I think that it is desirable to seek versatility not only for maps but also for these broad graphics use cases.
Well, I’d like to explore the layer again. Elements for embed of external resources used in svgMap to achieve similar layer functionality allow multi-level embed. As a result, the structure is tree-like, deviating from the basic layer concept. And in SVGMap, this tree structure is used not only as a superordinate concept of layers but also as a structure for constructing a tile pyramid of multi zoom levels. As a result, it is possible to implement a highly efficient vector tiling method. This is described in the second half of the slide of Quad Tree Composite Tiling previously introduced. The tiling architecture of SVGMap is notably different from that of map / geo community.
That is my study so far. Because it could not take much time, it may contain many misunderstandings.
I’m looking forward to discussing with you on TPAC.