Re: [OpenMap Users] Mixing DTED levels in a single directory Tree

From: Don Dietrick <dietrick_at_bbn.com>
Date: Fri, 27 May 2005 16:40:15 -0400

HI John,

On May 27, 2005, at 3:46 PM, Pearson John T Jr GS-13 453 EWS/EWA wrote:

> Don & List:
>
> We've recently started working with Level 2 DTED. I notice from the
> Openmap.properties file that you seem to indicate levels 0 and 1
> can be
> mixed in the same directory tree, but not level 2.
>
> Is there a reason for this? As far as I know all Level 0 data has
> a ".dt0"
> extension, level 1 data a ".dt1" extension, and level 2 data a ".dt2"
> extension.

There is a reason - the code was originally written to work like you
expect, but several years ago NGA started distributing DTED level 2
data with a .dt1 extension. So the level2 paths hack was implemented.

> I have been mixing the data on my PC and haven't had a problem
> until now.
>
> The dted coverage layer seems not to recognize DTED level 2 data
> despite the
> paths being set appropriately.

The DTEDLayer needs to be updated, I've been planning an overhaul but
haven't started work on it yet. It'll like of look like the
DTEDFrameCacheLayer.

If you use the DTEDFrameCacheLayer, you have to add a
com.bbn.openmap.dataAccess.dted.DTEDFrameCache to the MapHandler.
That DTEDFrameCache lets you set a StandardNameTranslator object,
which is an object that finds the DTED data for the DTEDFrameCache.
The StandardNameTranslator expects to see .dt2 extensions for level 2
data. The java docs for that DTEDFrameCache has details on how to
configure it with properties.


> Also, can you use the DTED frame cache mechanism and the more
> traditional
> OpenMap mechanisms at the same time?

I'm not sure what you mean. The DTEDFrameCache is based on an
internal cache mechanism.

Hope this helps,

- Don

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Received on Fri May 27 2005 - 16:40:39 EDT

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