@ghislainp Polar heatmap is not supported at the moment. It makes sense to plot such a heatmap when you intend to map your data to a cyclical colorscale, according to their polar angle. In this case you should use a circular colorscale such as hsv or phase (from matplotlib cmocean). See the attached images.
Here is an example of polar heatmap:
https://plot.ly/~empet/13959. If you are interested in this type of heatmap, and your data is in cartesian coordinates, drop here a message and I’ll post a jupyter notebook illustrating how to define it.
HSV colorscale:
phase colorscale:
