Archived Forum

This is a new multigraph data viewer for emoncms, on emoncms.org for testing now and github https://github.com/emoncms/graph

Preamble
Last December I built a minimal data viewer for emoncms data called phpfinaview here. It featured amongst other things a multigraph data viewer with one click add remove feed left/right axis control and a list of the stats of each feed below the graph view. I used it a lot to explore data from my heatpump, the combination of the easy feed addition/removal and the stats at the bottom meant I could get at COP figures at mean outside temperatures and flow temperatures much faster. I also added a feature to create a histogram of the data in the view to see at which power levels the heatpump used more energy over time without needing to create histogram feeds which are not supported on the low write mode of emoncms anyway.

In order to make it possible to have this functionality from within emoncms I have put this together as a new module called graph which can replace the default feed data viewer in emoncms. So that when you click on the view/eye icon on a feed it goes straight into this multigraph style environment.  This is up and running now on emoncms.org to test and the module is available on github here https://github.com/emoncms/graph

Here are a few screenshots of what it can do:

Main view:

The feed selection pane on the left is responsive and disappears when the screen size is less than 1024px wide.

Histogram

View any feed as a histogram of the amount of time spent at the range of values in the view or in the case of power feeds the amount of kWh consumed at a given power level. The resolution of the histogram can be selected in the view.

Smoothing

Useful where data is noisy and its hard to make out a pattern, this is a moving average the number of points to average can be selected on a per feed basis:

Export view as CSV

Choose the time format: unix timestamp, seconds since start or date time string
Choose what to do if missing values are present: show, remove, use last valid value

Further development

• Ability to save and load saved graph's (uses same json structure as multigraphs)
• Import graph built using graph into dashboards
• Tooltips
• Datapoint editor
• Selectable line or bar graph form on a per feed basis
• Selectable line color and fill.
• Realtime data view

Im thinking that saved graphs produced with this module could ultimately replace vis module visualisations: realtime, rawdata, bargraph, graph, multigraph. In-built data editing could replace edit daily and edit realtime. The histogram calculation on the fly can replace the need for the histogram input processor, feed engine and visualisations and on the fly averaging could replace the need for the PHPFiwa feed engine.

I imagine there will be some bugs in this for a bit so please let me know if you see anything that's not quite right or ideas for improvement.