Aggregator Function Not Firing in Demo

Datashader
,
1

Trying the example for datashader using taxi data here: https://datashader.org/getting_started/Interactivity.html

Whenever you change the field selection, the aggregator function never fires. This parameterized control does not work.

What is required to get this function to fire?

2

Looks like ipywidgets wasn’t installed when the holoviz-tutorials were installed so I installed that.

No luck. The aggregator function still does not fire when a new field selection is made.

What’s the secret to get this to work?

3

https://datashader.org/getting_started/Interactivity.html doesn’t have an example using taxi data, so I assume you are talking about https://examples.pyviz.org/datashader_dashboard/dashboard.html (linked from that page). If so, I’m guessing what you’re noticing is not that the aggregator function is not being called, but that the results of the default aggregator function “count” are the same regardless of the value of Field, because count is just counting records by default. If you change the Agg_fn to something else like Max that does use the information in the field, then you should notice that the display updates each time you change the Field. If that’s what you’re noticing, then it is working as designed, but I agree it’s confusing!

4

I believe the demo used servable() to render the panel with the map. I added a print statement to the aggregator function and it did nothing when selecting different fields.

I finally changed from panel.servable() to panel.show() which popped up the panel in another tab. This did work. Confirmed by print statement added to the function. It seems like .servable option doesn’t fully work. I would like to keep it all within the notebook, but popping out to another tab is fine since I get a bigger map view.

Now I need to figure out how to filter my data points by selecting values contained in other fields. I would also like to use a box select to grab points within the box and display details in a holoviews table. Any demos or examples on how I could do that by enhancing this demo?

Thanks