[GRASS5] reading DTED0

[Chris Thorne]

Hello,

I am having difficulty with DTED0 files downloaded from the NIMA web site.
My program appears to do exactly the same as in teh Grass dted reader.

The problem is:

The DTED0 records, like DTED1 start with a recognition sential of 170 (252 octal).
I have found that the sentinal is always where it should be (according to the DTED1/2 performance
specification) for the first record. For subsequent  records, if
I don't find it i I have to loop through the bytes until I I find it.  It takes normally 1 to 3 bytes to
find it for two samples in an Eastern Australia region and up to 9 bytes for some records in
two tiles (n39w077, n40077). This  is a variation that does not conform to the performance spec.

Is this variable record size a problem with the production of the files for download or is it in the
source data used to prepare the filed fro download.

My program has no such problems reading DTED1 data I have on CD, just the DTED0 from NIMA
web site.

I have sent email to NIMA using the feedback link on the DTED0 page but no response to my first email.
Just sent the above again - maybe someone will respond this time.
Anyone else know about this problem?

thanks,

Chris

--
Chris Thorne
Software Engineering Manager             .     Tel: +61 8 9333 8866
ADI Limited                          ,--_|\    Fax: +61 8 9333 8889
Perth, Western Australia            /      \   Email chris at ccis.adisys.com.au
20-22 Stirling Highway, Nedlands   :)_.--._/
WA 6009, Australia                        v



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