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20051122: IDV track altitude in meters only; time values?

>From: Stuart Wier <address@hidden>
>Organization: UNAVCO
>Keywords: 200511222339.jAMNd97s013416 IDV  track reading

Hi Stu-

>Try this if you haven't already. Download the file to disk, and read from ther
> e;
>it may not be working connecting to a track data source at a URL.

I tried that, but that's not the problem in this case.  The problem
is that the latitude and longitude variables are "lat" and "lon"
instead of "latitude" and "longitude".  I'm not sure if you can
change the file, but that would solve the problem in the short
term.  The old VisAD (1.2b2) reader used an alias mechanism
to equate lat with latitude and lon with longitude which is
why it used to work. The new Common Data Model reader doesn't
have that.

You might want to take a look at the trajectory conventions at:

http://www.unidata.ucar.edu/software/netcdf-java/formats/UnidataObsConvention.html

and make sure any new files you create adhere to these specs
for better compatibility.

In the mean time, we'll see if we can do something to get the
files working as they are.

Don



>Stu
>
>> 
>>>Check out the IDV track data file at
>
>http://geon.unavco.org/unavco/NETCDF/raypath_P_wave_30deg_timed_p3.nc
>
>>>There are times for each point on the path but when displayed as a track-alt
> it
>>>ude
>>>plot I don't see any times. The times do show up ok in the point data list.
>> 
>> 
>> Well, you're doing better than me.  The latest versions can't even
>> read that file as a track. :-(  As I mentioned before, we switched
>> from using VisAD to read the point and trajectory data to using
>> the nj22 Common Data Model work.  Unfortunately, this appears to
>> have broken some stuff.
>> 
>> However, if you want to see times with the track, then you'll need to 
>> load the data in as a Point data plot as well.  Then you can use
>> the options on the track control to display the path in relation
>> to the animation steps.
>> 
>> 
>>>Also, the color table range values appear to be in meters even though the da
> ta
>>> units are
>>>supplied as km. You can set the range for the bottom of the mantle at -28000
> 00
>>> meters
>>>but that may not be not obvious to the user who put in the data in km.
>> 
>> 
>> When I try this, it uses the generic Topography color table which
>> has a default range of 0 to 4000 m.  Since the default unit for
>> Alitude is meters, that's the range that is used.  You can change
>> the display unit to km through the DisplayControl's Edit menu
>> 
>> 
>>>I am using 1.2b2 so maybe this is ok in 1.2 or 1.3
>> 
>> 
>> Well, since we can't even read the file in those versions, I'd
>> say it's worse.  We'll try to get this fixed before the 1.3b1 
>> release next week.
>> 
>> Don
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