Mercator imagery layers publish incorrectly publish BoundingBox in lat/lon

I just noticed a bug in our osgEarth implementation of Cesium Ion where imagery layers from Ion would only partially show up on the globe. The reason for this is that Ion’s tilemapresource.xml file reports an SRS of EPSG:3857 (Mercator) but then reports the BoundingBox and Origin in lat/lon coordinates when they should be in Mercator coordinates instead. Origin and BoundingBox should match whatever SRS is reported, not lat/lon.

<TileMap version="1.0.0" tilemapservice="http://tms.osgeo.org/1.0.0">
  <Title>Imagery</Title>
  <Abstract></Abstract>
  <SRS>EPSG:3857</SRS>
  <BoundingBox minx="-180" miny="-85.05112878" maxx="179.994298457408" maxy="85.05112878"/>
  <Origin x="-180" y="-85.05112878"/>
  <TileFormat width="256" height="256" mime-type="image/png" extension="png"/>
  <TileSets profile="mercator">
    <TileSet href="0" units-per-pixel="156543.033928041" order="0"/>
    <TileSet href="1" units-per-pixel="78271.51696402048" order="1"/>
    <TileSet href="2" units-per-pixel="39135.75848201024" order="2"/>
    <TileSet href="3" units-per-pixel="19567.87924100512" order="3"/>
    <TileSet href="4" units-per-pixel="9783.939620502561" order="4"/>
    <TileSet href="5" units-per-pixel="4891.96981025128" order="5"/>
    <TileSet href="6" units-per-pixel="2445.98490512564" order="6"/>
    <TileSet href="7" units-per-pixel="1222.99245256282" order="7"/>
  </TileSets>
</TileMap>

@jasonbeverage

Thank you for bringing this bug to our attention! We are currently working on a solution internally. I will update you with a timeline as soon as possible. In the meantime, let me know if you have any suggestions, questions, or comments.

-Sam