@fil am I doing the right thing, here?

with serialize, you mean? I think the challenge is that the *chart* object is HTML and not SVG, so you can't put it directly into the other svg. Also I'd recommend to use htl.svg`` instead of html``

Thanks! I am going to convert to Plot.geo soon and also follow your suggestion above and in other exchange so to also have the "Download PNG" working (so that my colleagues can get the PNG easily)