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[sdw] WebVMT: Revised Zoom Syntax

From: Rob Smith via GitHub <sysbot+gh@w3.org>
Date: Tue, 19 Jun 2018 11:02:16 +0000
To: public-sdwig@w3.org
Message-ID: <issues.opened-333622308-1529406135-sysbot+gh@w3.org>
rjksmith has just created a new issue for https://github.com/w3c/sdw:

== WebVMT: Revised Zoom Syntax ==
WebVMT zoom is currently set by the `level` parameter, which is defined as the integer value of zoom for the associated `tile-url`. However, this no longer makes sense as `tileurl` is now an attribute of the &lt;track&gt; element, so the zoom level units are no longer known within the VMT file.

To rectify this, I propose changing the zoom level to a `radius` in metres. This provides a consistent display for all different shapes and sizes of screen, ensuring that geolocations within a known distance of the display centre are visible, regardless of other factors.

For example:

    WEBVMT

    MAP {
      centre: 51.162 -0.143;
      zoom: 10; // radius in metres
    }

    00:00:03.000 -->
    <panto latLng="51.508 -0.077" end="00:00:05.000"/>

    00:00:06.000 -->
    <zoom radius="40"/>

The intention is that this radius is a minimum level of visibility, i.e. to guarantee display, rather than an exact fit to screen.

Please view or discuss this issue at https://github.com/w3c/sdw/issues/1049 using your GitHub account
Received on Tuesday, 19 June 2018 11:06:49 UTC

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