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w3c / sdw

Repository for the Spatial Data on the Web Working Group
https://www.w3.org/2020/sdw/
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WebVMT & MapML: Shared goals #1273

Open Malvoz opened 3 years ago

Malvoz commented 3 years ago

FYI: The Use Cases and Requirements for Standardizing Web Maps identifies several capabilities that may relate to synchronizing video to map presentation. I've opened an issue for the use case(s) of synchronizing audio/video to map presentation: https://github.com/Maps4HTML/HTML-Map-Element-UseCases-Requirements/issues/248.

WebVMT states:

It offers presentational control of the map display, e.g. pan and zoom, and annotation to highlight map features to the viewer, e.g. markers and labels.

These (including many of the planned features) are features that MapML is intending to standardize (based on the requirements concluded in the UCR for Standardizing Web Maps).

Due to shared goals I think it'd be appropriate for WebVMT to include an informative reference to MapML, perhaps in the note on UAs handling rendering (as UA handling of map rendering is the goal of MapML).

https://github.com/w3c/sdw/issues/1019#issuecomment-373758043:

As map rendering is not supported in user agents currently, there is a more general question of how to handle the transition if they do support it in future, which is probably beyond the scope of this project, though still worth discussing in a separate thread.

Is there a polyfill available for WebVMT? The Maps for HTML CG could possibly experiment with the <mapml-viewer> custom element (MapML polyfill) for WebVMT integration.

The WebVMT longitude setting is identified by the string "lng", whereas MapML defines the lon attribute for the <map> element. Should the specs settle on the same, for developer convenience?

/cc @rjksmith, @prushforth

rjksmith commented 3 years ago

@Malvoz Thanks for reaching out.

  1. Perhaps I've misunderstood but I see no mention of the mechanism by which to synchronise location content with the media timeline in Maps4HTML/HTML-Map-Element-UseCases-Requirements#248. This is the key issue that WebVMT addresses for timed metadata and I'm unclear how this problem can be overcome using only static HTML.

  2. WebVMT is deliberately agnostic of the underlying web map API and aims to make dynamic media metadata more accessible in user agents - particularly through JavaScript APIs due to the transient nature of the content.

  3. A version of the TrkdVideo engine provides WebVMT support for the webvmt.org website. WebVMT content can be manually tested using the mobile demo which includes syntax checking and error reporting features. This code already supports multiple web map APIs and I'm happy to discuss adding MapML as yet another entry in the current list to enable experimentation in the Maps4HTML CG.

  4. The geospatial community seems to favour 'lon' and the web community prefers 'lng' as an abbreviation for longitude. WebVMT uses 'lng' as the web is its primary focus.

I hope this helps.