GPS based data acquisition?

[phiscock-g851W1bGYuGnS0EtXVNi6w at public.gmane.org]

> On Wed, May 26, 2010 at 11:31 AM,  <phiscock-g851W1bGYuGnS0EtXVNi6w at public.gmane.org> wrote:
> ...
>> There may be some advantages to using 'gpsd' as an intermediary, but in
>> any case we can just decode the ASCII data.
>>
>> Our voltmeter software can be set to acquire data at any rate (over
>> about
>> 2 readings per second), so I picture patching that with a routine that
>> captures the most recent GPS data. The same routine would write a
>> voltmeter-data plus gps-data record to a file.
>>
>> Now I need to figure out how that data could be superimposed on a map...
>
> I'm surprised that you can get a good reading of light pollution from
> a car.  Do you park the car and cut the lights to take the readings?

It depends what you're trying to measure. There is a 'sky quality meter'
(SQM) which measures the darkness of the sky. Astronomers use it to
measure the quality of the viewing.

I'm more interested at this point in the lighting of Toronto streets. I
would like to see whether the streets are illuminated above, at, or below
the standard. (IESNA and CIE both have standards for street light level.)
If the light levels are above standard, then that's clearly a waste of
energy. Another issue is uniformity: lighting designers try to ensure that
the light level does not change between lamps.

I just finished a paper that suggests street lighting contributes about
30% of light pollution, so it's an important issue.

I picture the light sensor mounted on the car (or bicycle!) pointing
upward, with a shield so that it's not affected by car headlights.

Rob Pike (of Unix fame) did a study in the Toronto area of light
pollution, back in the 70's I believe. So it's been a long time since
anyone measured this.

Peter


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-- 
Peter Hiscocks
Syscomp Electronic Design Limited, Toronto
http://www.syscompdesign.com
USB Oscilloscope and Waveform Generator
647-839-0325

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