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A few questions
Posted: Tue Dec 02, 2008 6:59 am
by tmagan
I have a couple of questions about the 'Data Retrieval Window':
1) It seems like 'NIU' was added recently. Is that true?
2) If you select some of the METAR sites plus both MADIS files, is that a bit of overkill?
3) If you select some of the METAR sites, but one of them includes observations two or three hours old, does D.A. automatically filter out the old observations?
4) It seems to me the Buoy observations come in a few times a day. Does D.A. filter those out, or just leaves the 'old' observations in?
Posted: Wed Dec 03, 2008 2:10 am
by Shannon Key
Here's a reply to your questions from Tim:
> 1) It seems like 'NIU' was added recently. Is that true?
Probably. I don't know when it was added... I just add them when
I see a new source come online.
> 2) If you select some of the METAR sites plus both MADIS files, is
> that a bit of overkill?
Not if you are looking at small-scale areas. They will complement
each other.
> 3) If you select some of the METAR sites, but one of them includes
> observations two or three hours old, does D.A. automatically filter
> out the old observations?
Digital Atmosphere attempts to use the newest observation if
multiple observations appear. Sometimes observations are outside
of the time range bound (see the Workchart Toolbox tab on the left
under "Time Selection > Surface") -- if this is set to "1 hour"
then observations 3 hours old will not even be processed.
> 4) It seems to me the Buoy observations come in a few times a day.
> Does D.A. filter those out, or just leaves the 'old' observations
> in?
It will plot them if they fall within the upper and lower time range
set by the Toolbox Workchart tab on the left under "Time Selection".
There are many ways to use it to set which times will be imported.
Tim
Please feel free to ask if you need further clarification or have more questions.
Shannon
Posted: Thu Dec 04, 2008 10:51 pm
by tmagan
Sometimes, when I use the 'Data Retrieval Window', I'll get an error box saying 'Digital Atmosphere encountered an error: Read beyond end of file'. What does this mean?
Posted: Fri Dec 05, 2008 10:47 pm
by Shannon Key
It occurs when a data record structure doesn't fit the
expected structure and accidentally reads past the end of
the file. There are sometimes changes to the data structures
in Digital Atmosphere; for example this year the meteorological
data point structure used in ALL imported observations was
changed. That problem can be avoided by properly patching
Digital Atmosphere (not mixing and matching old internal files with
new ones).
Tim
tmagan, please let me know if you need further clarification.
Posted: Mon Dec 08, 2008 1:02 pm
by Wally Mayo
"Digital Atmosphere attempts to use the newest observation if
multiple observations appear."
Hmmm, are you sure? I had always found that DA would plot the first obs and ignore any later ones (unless you manually limited it in the panel to i.e. last 20 minutes or so). Problem was if you limited it to 20 minutes you eliminated may plots that came only every hour. Perhaps this is a change, I'm about to install 1.4.
It would be GREAT if that bears out. I would like to see it plot last report as default (with whatever time frame is chosen).
Great work.
Posted: Thu Dec 11, 2008 5:18 pm
by Shannon Key
Wally Mayo wrote:"Digital Atmosphere attempts to use the newest observation if
multiple observations appear."
Hmmm, are you sure? I had always found that DA would plot the first obs and ignore any later ones (unless you manually limited it in the panel to i.e. last 20 minutes or so). Problem was if you limited it to 20 minutes you eliminated may plots that came only every hour. Perhaps this is a change, I'm about to install 1.4.
Wally,
I spoke with Tim about this and he is going to look to see if it's working the way he stated. If not he will rectify it. We are starting work on another patch to fix the Mercator projection plotting and a few other things, and this will be in the list of things to do for that patch.
Shannon