<p>I have noticed this also can happen if you are looking at a larger window of time than can be handled by your screen resolution. My guess is that the FFT bin size at these larger display windows is smaller than the pixels that can be displayed by my screen.</p>
<p>For example, if I look at 10 seconds of data, some of the contours are slightly off from where they should be:</p>
<p><a href="https://i.sstatic.net/tZB0G.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/tZB0G.png" alt="Screenshot of a Spectrogram in Pamguard with whistle contours displayed over the spectrogram. Shows 10 seconds of data. Some of the whistle contours do not properly line up with the detected whistle." /></a>
The green and teal contours at the very start of this file are just below the actual whistle (dark part above them).</p>
<p>But, if I reduce the window size to 5 sec, then it lines up properly.
<a href="https://i.sstatic.net/Jd1LA.png" rel="nofollow noreferrer"><img src="https://i.sstatic.net/Jd1LA.png" alt="Screenshot of a Spectrogram in Pamguard with whistle contours displayed over the spectrogram. Shows 5 seconds of data and all whistle contours line up with the correct whistles." /></a></p>

CC BY-SA 4.0
2024-01-22T16:21:39.597Z
2024-01-22T16:21:39.597Z
selene
<p>The data are stored as FFT bin number, not the actual frequency. Perhaps that was a mistake, but it's how it is. If you change the FFT length and hop back to what it was when you processed the data, everything should line up again. You may need to restart PAMGuard after changing the settings.</p>

CC BY-SA 4.0
2022-07-21T10:28:19.213Z
Great- thanks Doug!
Laura P
CC BY-SA 4.0
2022-07-21T10:20:46.580Z
2022-07-21T10:20:46.580Z
Doug Gillespie
<p>In PAMGuard Viewer Mode, my whistle contours have become decoupled from the spectrogram on the frequency axis. I think I've accidentally changed a setting as I referred back to screenshots from this exact dataset where the contours match the fundamental frequency contour (i.e. it isn't an issue with my whistle detection settings when I processed the data in PAMGuard, I think it's something I've accidentally changed in viewer mode).</p>
<p>Anyone know how to fix this, please?</p>
<p><a href="https://i.sstatic.net/1mSU4.jpg" rel="noreferrer"><img src="https://i.sstatic.net/1mSU4.jpg" alt="enter image description here" /></a></p>

CC BY-SA 4.0
2022-07-21T17:05:21.487Z
If one of the answers below answers your question, please 'accept' the answer by checking the checkmark under the vote tally. See stackoverflow.com/help/someone-answers
Shannon
<pamguard><whistle-moan-detector><pamguard-viewer-mode>
PAMGuard whistle contours out of sync
# PAMGuard whistle contours out of sync

(Asked by: username_0 on 2022-07-21)

In PAMGuard Viewer Mode, my whistle contours have become decoupled from the spectrogram on the frequency axis. I think I've accidentally changed a setting as I referred back to screenshots from this exact dataset where the contours match the fundamental frequency contour (i.e. it isn't an issue with my whistle detection settings when I processed the data in PAMGuard, I think it's something I've accidentally changed in viewer mode).

Anyone know how to fix this, please?

[![enter image description here](https://i.sstatic.net/1mSU4.jpg)](https://i.sstatic.net/1mSU4.jpg)

**Tags:** pamguard, whistle-moan-detector, pamguard-viewer-mode

> **Comments:**
> **username_1**: If one of the answers below answers your question, please 'accept' the answer by checking the checkmark under the vote tally. See stackoverflow.com/help/someone-answers  

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## 2 answers

### Answer by username_3 on 2022-07-21. Score: 11 | Accepted answer

The data are stored as FFT bin number, not the actual frequency. Perhaps that was a mistake, but it's how it is. If you change the FFT length and hop back to what it was when you processed the data, everything should line up again. You may need to restart PAMGuard after changing the settings.

> **Comments:**
> **username_0**: Great- thanks username_3!  

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### Answer by username_2 on 2024-01-22. Score: 0

I have noticed this also can happen if you are looking at a larger window of time than can be handled by your screen resolution. My guess is that the FFT bin size at these larger display windows is smaller than the pixels that can be displayed by my screen.

For example, if I look at 10 seconds of data, some of the contours are slightly off from where they should be:

[![Screenshot of a Spectrogram in Pamguard with whistle contours displayed over the spectrogram. Shows 10 seconds of data. Some of the whistle contours do not properly line up with the detected whistle.](https://i.sstatic.net/tZB0G.png)](https://i.sstatic.net/tZB0G.png)
The green and teal contours at the very start of this file are just below the actual whistle (dark part above them).

But, if I reduce the window size to 5 sec, then it lines up properly.
[![Screenshot of a Spectrogram in Pamguard with whistle contours displayed over the spectrogram. Shows 5 seconds of data and all whistle contours line up with the correct whistles.](https://i.sstatic.net/Jd1LA.png)](https://i.sstatic.net/Jd1LA.png)


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