Category Archives: visualization

How to improve PG&E’s usage and charges graph

I was pleasantly surprised that PG&E includes graphs for usage and billing history on their website. You can view electricity usage and charges in a pretty neat (but simple) graph.

I’ve been living in my current apartment since March 2007 which is the first data point on the x-axis. I wonder if there is a limit to how many months they show?

Making it easier to compare

The electricity usage is obviously seasonal and you can see the ups and downs in the graph. It would make more sense to have a 1 year wide graph and overlay last years data over the current data in a line or area chart. This would make the comparison easier and more meaningful. Alternatively a 12-months trend line would provide additional information but with a significant delay.

I created the above graph using Google Docs. I like the look and it makes comparing the charges from one year to the next a lot easier. Even adding another year shouldn’t impact readability. Now I have to find out why I’m paying 15-20% more this year.

It would also be interesting to compare usage and charges in the same graph. Am I paying more because I’m using more or because electricity is more expensive?

What are other companies providing?

Not much. I would love to have similar graphs for my bank account, credit card and phone bill. In fact I initially started this post rambling about AT&T and how they make it really hard to look at usage history. I’ll save that for another post. Maybe I’ll whip out Greasemonkey and create a little script…

Update 7/8/08: I’ll have to check out Skydeck for my AT&T billing needs. Still in closed beta.

Get to work faster with more accurate traffic reports

I spend more than 2 hours a day commuting to work. Accurate traffic conditions and avoiding the worst delays and accidents are key. I’m using and Yahoo! and Google Maps to get up to date information on traffic. Note: Why don’t the maps services offer an easy way to look at your commute every day?

I’m convinced that we can improve on the quality of the traffic reports. And I found the ideal data source: The mobile phone providers!

More sensors = better data

Think of a mobile phone as a sensor. Thousands of cars are using a given section of the freeway at the same time. The mobile phones in the cars can be tracked by the carriers. Plotting the movements on a map will result in the most accurate and up-to-date traffic conditions. We could have the average speed for any given quarter mile in real time!

Red/yellow/green – what’s the trend though?

Most traffic services currently use green/yellow/red to indicate the speed of the traffic. This is insufficient. Will yellow turn into red or green? The time dimension is lacking here. A simple arrow indicating the trend for the last 10 minutes would help. E.g. It’s yellow right now and has been getting slower in the last 10 minutes.

Speed graphs including historical information

This could be further enhanced by adding a graph for the speed where the x-axis represents the last 30-60 minutes or so. This could even be a 3D graph adding the data for the last 7 days.


The privacy of the mobile users has to be protected obviously. No tracking of individuals is allowed. Only the aggregate information is to be used.