[Geysers] Webcam and other times 8/2/2011

[Graham Meech]

Thanks for the comments on the log times Dave.  We try and clean up the data
as best we can and appreciate comments to correct entries in the logs.  Both
of the online logs now exchange data and have different approaches to deal
with potential duplicate (or more) entries but the Beehive entries didn't
clean up properly.  It is not unusual now for webcam viewers to enter a time
and then someone in the park enters an on-site time too which we always like
to see.  We augment the logs with the listserve reports, times from FaceBook
and other places.  It's always nice to see the reports from the LGB too.  

I want to send out a thank you to both Allan Glennon and Jake Young who have
created the databases, web sites and Android app.  They have invested a lot
of time to create these useful tools for accessing current eruption
information and allowing us to see lists of recent intervals so we can see
what Beehive or other geysers have been up to recently (yeah Beehive is too
regular isn't it?).  These go well together with Ralph's electronic data
which gives us the 24x7 picture and the NPS logbook.

Graham Meech

-----Original Message-----
From: geysers-bounces at lists.wallawalla.edu
[mailto:geysers-bounces at lists.wallawalla.edu] On Behalf Of David Monteith
Sent: Wednesday, August 03, 2011 4:08 AM
To: Geyser Observation Reports
Subject: Re: [Geysers] Webcam and other times 8/2/2011

The Beehive 1508 wc time is incorrect.  The streaming camera showed
Beehive starting at 1501 and the still camera showed it ie at 1502.

Based on the streaming and still cameras, Old Faithful erupted at 1451
not 1446.

I had assumed that the Beehive error might be due to a delay of the
streaming feed at the observer's computer but that doesn't explain the
Old Faithful time.   

Four times during the past couple weeks I've spent an evening thoroughly
checking the posted webcam times against recordings of both the
streaming camera and still cameras.  I've found very few errors.  And
most of those are similar to errors seen in the VEC logbook (primarily
start time differences of a minute.)  

It is possible to obtain accurate times from the streaming webcam but
this needs to be done with care.  The webcam operators see the stream
with very little delay so their times are usually accurate.  For those
watching the stream "live" on their computer in most cases the media
player is actually buffering the stream before showing it to you.  It
stores the stream in memory and then displays it so the video will play
smoothly.  How long the delay is varies from as little as 15 seconds to
up to 2 minutes.  To make matters worse, we've seen problems with the
stream signal, frequently seen as jerky, stop and start video.  These
delays can build.  On one particularly bad day, the delay on the "live"
view reached two hours on my machine before the server or my computer
finally gave up and disconnected.  I think most people reporting times
from the webcam are taking precautions to make sure their times are
accurate.  

I've found that the delays are very minimal, predictable and
controllable if I record the stream and watch it later.  Working with
Tara while she was in the geyser basin, we determined that the delay on
our system at home was consistently 3 to 6 seconds.  I have the added
advantage though that I can pause, backup and fast forward to determine
start times and durations.  And most importantly, I find the UGB stream
provides me with a nice geyser fix when I can't get to the park.  

Please continue to post your webcam observations.  And for those wanting
to use the data, I believe you can feel fairly confident about it.  But
be aware of the limitations of the technology both when reporting times
and when using the data.

Dave