

PressureNET Data Visualization [Android barometer network] - cryptoz
http://www.cumulonimbus.ca/pressurenet-data-visualization/

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shawn-butler
This is an interesting use of the barometer/GPS hardware but I guess I'd
appreciate a little help on understanding its greater utility?

Atmospheric pressure doesn't change that much. It's pretty much the same where
I am as it is 20 miles away at my nearest airport. What is the need I'm not
seeing for a sensor net of higher granularity than already exists? Is it for
tracking weather related to very intense pressure gradients like tornadoes? I
thought we had radar that did a pretty good job of that.

Also isn't the accuracy of the barometer really, really poor when it is in
motion? I thought they just used it to get a rough sense of altitude and speed
when GPS was too costly/unavailable? Cool work.

~~~
cryptoz
Weather prediction is pretty miserable right now. If you turn on the TV or go
to a website to get a weather forecast, you will be told that "it might rain
later, somewhere near you, maybe". I think that's unfortunate. For many
people, that's much worse than unfortunate, it's _terrible_. An extreme
example would be farmers in places that are being affected by changing weather
patterns due to climate change. Knowing with high accuracy on a local scale
_when it will rain_ could be very very useful.

I'll address some of your points.

> Atmospheric pressure doesn't change that much. It's pretty much the same
> where I am as it is 20 miles away at my nearest airport.

Well, yes. The changes are subtle. But that just means I have a tough job
ahead of me. Small changes != useless data. Also, is the weather the same at
the airport 20 miles away as it as your house right now? It might be. Is it
always the same? Most definitely not.

> Also isn't the accuracy of the barometer really, really poor when it is in
> motion?

The accuracy is very high. The barometers are very sensitive, so sensitive
that if you move your phone from your feet to your head you will see the
change in pressure due to the change in altitude. This adds noise to the data,
lots of noise in fact, but it's something that we are working to overcome. In
building the visualization tool, we've found that at larger scales the network
makes it obvious which changes are weather-related and which are noise. At
smaller scales, we must do some work to filter it out.

> I thought they just used it to get a rough sense of altitude and speed when
> GPS was too costly/unavailable?

That's why they are included in the devices, yes. But I think there are many
greater uses for them, such as building a global network of barometers. Did
you click through to the actual visualization tool, at
<http://pndv.cumulonimbus.ca>? You will see that we have collected some really
incredible data that nobody else seems to have.

\--

The main point here is that this is an experiment. I think it is very likely
that having higher resolution data will increase the accuracy of small scale,
short-term, local weather prediction. I'm working some some atmospheric
scientists (Cliff Mass, for one) who are very excited about the project. We'll
see where it goes!

~~~
shawn-butler
Yes, that's what I meant by poor. The sensor noise makes it a difficult
instrument when in motion.

Yes I looked at the visualization. Very cool. I wasn't trying to be negative
just wondering about how it differs from data sets currently available and
what kind of value I could add on top of it. Thanks for info, it is kind of
exciting. What lept into my head was some way of getting a measure of wind
speed in addition to pressure but I don't see how that would work with the
hardware we have.

