Box select support

[jbednar]

Once there is hover-tool support (issue #91), it would be great if we could support a box-select tool as well, providing essentially the same information as hovering but for a bounding box specified by the user interactively. Adding such support seems relatively straightforward once the hover tool support is in place, but it requires a dynamic query rather than static information provided when the plot is created. Even so, the data can presumably be computed directly from the static information already provided, and so it should not require re-running any of the stages of the datashader pipeline.

Lasso-tool support may make sense as well, again just as a selection of the existing aggregate bins.

[Tisagh]

I found this while searching for some sort of select tool to use with Datashader.

I can subsample the data just fine and use in Bokeh or Holoviews with Bokeh on the backend but when using my full dataset neither can display the plots without slowing down the PC extremely. When I display with Datashader the selection tools don't work.

Is there a recommended work around for displaying datasets > 1M points with selection capabilities?

[jbednar]

Sure, for now you just have to do it manually. My proposal above is for us to do most of the work for you, and to do it using the aggregated data so that it's super-fast, but you can always add selection tools and compute ranges "by hand". There's an example at https://github.com/pyviz-demos/glaciers , which can be run live on binder: https://mybinder.org/v2/gh/panel-demos/glaciers/master?urlpath=/proxy/5006/app

[Tisagh]

Sure, for now you just have to do it manually. My proposal above is for us to do most of the work for you, and to do it using the aggregated data so that it's super-fast, but you can always add selection tools and compute ranges "by hand". There's an example at https://github.com/pyviz-demos/glaciers , which can be run live on binder: https://mybinder.org/v2/gh/panel-demos/glaciers/master?urlpath=/proxy/5006/app

Thank you

[jbednar]

I think the recent link_selections support in HoloViews addresses some of this need, but it's still a relevant feature request: draw a box or lasso, then show via hover the aggregated values in that region.