Layering with z-index works when using layergroups – but is there any working way to have another layer with circles or other elements ontop of a layer with a heat-map?
The heat-map seems to be always on top – except for single markers (circle-markers also don't work).
Using Mapbox/leaflet and https://github.com/Leaflet/Leaflet.heat
Best Answer
It's not a bug like @chkri mentionned.
It's just the way Leaflet handles its divs where it draws svg and where it draws canvas.
SVGs (basically everything extending L.Path) are drawn on a div container (leaflet-overlay-pane) with a smaller z-index then the div containing the heatmap canvas, and thus heatmap will always be on top of SVG markers.
A quick fix is to modify leaflet css and invert z-index of concerned containers.
Note that by doing this heatmap and L.Marker will all be behind SVG Markers.