I sort of got this to work, but it might not behave as you expect. One of the problems being the triangles are equilateral so it's not clear in which direction they are actually pointing.
The documentation at https://developers.google.com/chart/interactive/docs/points and https://developers.google.com/chart/interactive/docs/roles is not at all clear about how to do this but I found https://github.com/google/google-visualization-issues/issues/2353 which gave me a clue. https://jsfiddle.net/brisray/dcs7L589/ shows my effort at this with the sheet the data comes from at https://docs.google.com/spreadsheets/d/1WXWIJZHiOBDhRZcUOh2pr_eucUHeKy36XbWUqgKwYYI/edit#gid=0 I don't think I've fully answered your question, but it might give you a start. Ray -- You received this message because you are subscribed to the Google Groups "Google Visualization API" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. Visit this group at https://groups.google.com/group/google-visualization-api. To view this discussion on the web visit https://groups.google.com/d/msgid/google-visualization-api/4163b723-557f-4d91-ad95-9850240ab6eb%40googlegroups.com. For more options, visit https://groups.google.com/d/optout.
