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20050322: Range Rings Off

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  • Subject: 20050322: Range Rings Off
  • Date: Tue, 22 Mar 2005 08:45:42 -0700
>From: "Salottolo Greg" <address@hidden>
>Organization: NTSB
>Keywords: 200503221448.j2MEm5v2002814 IDV range rings

Hi Greg-

>Displaying a LEVEL II image for KAMA and using the lat/lon of the radar =
>antenna (35.2333 -101.70889) to center the range rings. The range rings =
>do not line up with the antenna location. They line up using WATADS and =
>the NCDC java nexrad viewer. Any thoughts.

It's a precision problem.  The radar data is located based on the
information in the nexrad station table which only has precision to
2 decimal places (35.23,-101.70).  When you use the higher precision
numbers, you'll end up in a different place.  If you want them
to line up, for now use the station selector and select Amarillo.

Thanks for bringing this to our attention.  I'll look into this
more deeply to see if we can get a better database for the lat/lon
locations (is 4 decimal places sufficient?).  Also, I found a 
couple of bugs:

- if you set the max radius lower for rings too low, you'll get
an exception.
- There is an option to change the location on a given radar
dataset (right click on the datasource and you'll see
Set radar location...), but the list does not come up.  I
can see that besides the list, we should allow the capability of
setting the lat/lon position as well.

Don
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