Closed astrobokonon closed 5 years ago
Pros:
Cons:
For "Active Plots" on a web page, the bokeh server seems to be necessary. It may be that some other plotting package for web would have a simpler setup, we don't know that yet. Bokeh seems to be widely used, well supported, and the code is Python. I suspect some of the "Cons" above can be overcome as we learn more about the package. The tooltips seem to be fairly configurable but I admit I've only played with them a little.
Also, I agree that the resulting web page/plots should look good. The main thing is to make the information the user needs as clear as possible and easy to see at a glance. To this end, perhaps each different kind of plot should be considered independently to determine what sort of display is best for the information in that plot. On the other hand, if the plots all look substantially different, the overall effect will be a mish-mash and look terrible.
For me, the following GIF shows my ideal for a non-frustrating user interaction with a plot of many different types of information:
The tooltip follows the mouse cursor position but displays the relevant data. Most importantly, the tooltip doesn't block the data you're trying to look at!
If you make a line plot then the tooltip ALWAYS follows the line. This is great for a time series that is simple, like every example available on the internet. It works both faster and nicer than plotly's equivalent which is also good.
Once you put your real data in, it's all downhill. The "T2" parameter on the ARC/LOIS instruments is a good example of this - it has a short period sinusoidal variation since it's ultimately tied to the facility chiller system which has a refrigeration cycle of its own. This GIF was captured at 30 Hz; it's even worse at the full monitor refresh of 60 Hz.
Switching to a scatter plot instead seemed like a good idea, since the hover/tooltips for those is more flexible. But it turns out that if you have many points near your cursor (because there was a quick change, or your time range compresses things) it just shows you ALL the points that are within some unconfigurable tolerance of the mouse position. It's also not possible to do a connected scatter plot natively - you have to draw the line, then draw the data markers separately. I'm not a fan of doing 2x draws for every single quantity since Bokeh would then embed the data 2x for every series in the resulting JS/HTML.
Both of these are old issues with Bokeh (the original issue dates back to 2014), and not much has really been done since then. My last hope for Bokeh lies in the CustomJSHover method, but if that doesn't improve things then I'm inclined to ditch Bokeh for now and start investigating plotting in JS directly.
This took a large number of obscenities to get sorted out, but it's now complete and I understand why and I like it and I can recreate it for other plots.
Basically, I created a list of patches whose x coordinates were the coordinates of adjacent datapoints with y coordinates that span the initial Y range (for CCD Temp, which is "y1"). I then added those to the main Bokeh ColumnDataSource, plotted them, and set the HoverTool to ONLY act on that set of patches. It's important to put everything in the same ColumnDataSource since the HoverTool can only get values within a single one of those; you can't reference a separate ColumnDataSource.
That makes the tooltips valid, highlight only the points actually in the patch, and it's not that tremendous of a pain to do. I'm happy with this for now, so I'm content to close this issue and finally move on with my life.
Working as of e525327c0d002c1b63ec2fdecf61a08ba51e2482
Intro/Scope
This is an attempt to survey what's possible with each potential plotting package. Digging into bokeh a bit more (as part of my work furthering issue #4) I'm wondering if bokeh is the tree we should be barking up and whether there's a better option out there. This issue is an attempt to document some of that searching process.
Since the vast majority of things are time series data such as temperature, humidity, dew point, etc., I've focused on what I feel is most important.
Ranking considerations
Open Questions for All Packages
If the user changes the time range in one plot, should the time range in the other plots change to match?
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Tools Compared