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Universite-Gustave-Eiffel / NoiseCapture

Android App dedicated to the measurement of environmental noise.
http://noise-planet.org/fr/noisecapture.html
GNU General Public License v3.0
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Unit inconsistency in web page, app and raw data track files #335

Open Oldfield007 opened 3 years ago

Oldfield007 commented 3 years ago

Hi,

Can you please clarify the following in regards to the units used in the reference material, display and data files. I believe there is an error in the reference material showing all Leq data rather than LAeq, as a Leq = dB whilst LAeq = dB(A).

https://noise-planet.org/noisecapture_exploit_data.html#raw_files

Under the heading of:

  1. Direct reading: 2. Resulting page text says "Presents the physical indicators (average dB, time repartition, ...) resulting from the measurement." Should the average dB be dB(A) as these are the units used in the screen display?

  2. Local data: "The meta.properties file" information shows the sound pressure level as "Leq_mean: measure's mean Leq". This does not equate to the data file or the screen result shown in the circle which is in xx dB(A). Note that the dB(A) = LAeq whilst dB(Lin) of dB = Leq.

What does the "mean" actually represent; is it the integrated sound level measure of all the 125ms readings for the duration of the time the measurement is taken?

  1. Local data: "The track.geojson file" Is the raw data frequencies (octave bands) in dB ie Leq? Normally sound level meters record the sound pressure in dB not dB(A), but if the "Leq_mean" is in dB then it is out of sync with the display screen that shows dB(A).

In the screen shot (Integrated map.png) there are 3 pieces of information. The raw data web page, the meta properties file and the results screen.

Links below:

https://noise-planet.org/noisecapture_exploit_data.html#raw_files

Integrated map

Screenshot_20210226-121829_NoiseCapture meta.properties.txt track.geojson.txt

I have complied all the above question so that you can visually see how they relate. I have represented each number as a red circle in the screen shot

(1) = the issue of sound pressure mean Leq vs LAeq. (2) = the frequency bands Leq vs LAeq (3) = the issue of the LAeq 65.9 dB(A) in the display does not equal the same units in the meta.properties as they are in dB represented as an "Leq_mean = 65.92." (4) = what units are the frequency bands in dB or dB(A)? Can these be added as most graphs show the units? (5) = what units are the Min and Max in dB(A) like the rest or dB? This is confusing. I suggest you make all the units

Thank you Regards Greg

nicolas-f commented 3 years ago

Hi,

Thanks for the detailed issue.

All data are LAeq 1s

125ms is only for display on the measurement activity.