Dominik Moritz

Yeah, it seems like a Vega issue from the discussion above. Let me move this issue.

@arthurfiorette can you take a look?

How is this different from a binned chart? Maybe with a smooth line.

I experimented with contour plots a bit last summer. While they look great, there are some challenges with overlapping contours if the data is faceted. I could not even use...

[Link to the editor](https://vega.github.io/editor/#/url/vega-lite/N4KABGBEAkDODGALApgWwIaQFxUQFzwAdYsB6UgN2QHN0A6agSz0QFcAjOxge1IRQyUa6ALQAbZskoAWOgCtY3AHaQANOCgATdHkw5QECJAroxrZLGxgA2hsNhgkdoyUB9WLoBOeKwA5VUPDcrEo+OADsAL7q9hCOzm4e6N5WAIwADAGQQSFhYABMAJzRdobxLu5eean5WTmhVuGpJbEOThVJKTip0nXBDd35UTGx5YlVaQBsfblWhdIto+3jydX+gf15AKwLI-ZjlatW+Zkbs93DpXHLh10FtWcDYFuRpQC6GouQGJ4A1lZOZJqDSQZBKIKaFzUKwGQyQAAeMKuUAAZoxkGJNACErcfHs4Qkka0jAklMgsTg8J5zPj7JAPMhCMdkYs6XgAJ6EZAAgCOrHQoWYOkYVEgpVZUHZRNikDRGIpjzxyMgHK5vP5gt0eBF3PFnxAkSAA).

Yes, this is not a bug in Vega but a missing feature. Contour plots in Vega use a single transform that computes density and the contour lines in one step....

@kanitw I don't think so because the density can be computed separately.

That would be awesome. But note that we won't be able to maintain it so please keep the code minimal (i.e. no extra dependencies). Also, please add some short docs...

This could be super useful for #510 but we probably want to consider revising the SQL representation in mosaic first.

Thanks for the link. I think we can make our lives a bit easier by generating SQL in different dialects from a structured format (which we already have in https://github.com/uwdata/mosaic/tree/main/packages/sql)....