Feature Request: Add Geo Arrow Icon Layer

[MMJ744]

Could you create a layer wrapper for the Icon Layer

I've been using the GeoArrowScatterplotLayer but wanted more control over what the rendered points look like, e.g shape.

I've taken a look at the source code for the layers but I can't quite figure out what would be different when wrapping the icon layer. Any chance of this layer being added, or more guidance on how I might be able to create/contribute it myself.

Thanks :)

[kylebarron]

I think you included the wrong link.

In any case, it should largely be copy and paste from the ScatterplotLayer or PointCloudLayer (I'd probably point you to the PointCloudLayer for reference, because the IconLayer probably shouldn't support MultiPoint geometries), but you also need to include the extra parameters to pass the iconAtlas, iconMapping, etc to the upstream layer.

[am2222]

@kylebarron can you please have a look at this PR (#129)?