Storing/Accessing stuff in a big terrain map
Ulf Wiger (AL/EAB)
Wed Jun 9 11:50:57 CEST 2004
Ooh, tricky. I guess you're talking about storing DTEDs (Digital Terrain Elevation Data) etc.?
One of my largely unsuccessful prototypes was 'gridfile', which was based on an idea for a symmetric multi-key file structure (Nievergelt & Hinterberger, from Stonebraker's "Readings in Database Systems, 2nd ed." 1994). I never got it to work satisfactorily, but the big culprit was the notion that the key(s) could be any legal Erlang term - this made bucket splitting and merging in multiple dimensions somewhat difficult, where the article simply used integer ranges in a virtual grid. Using standard DTED formats (e.g. http://www.caf.dlr.de/SRTM/produkte/SRTM-XSAR-DEM-DTED-1.1.pdf), one could make a specialized gridfile that might scale a whole lot better than my version did.
My attempts can be found at http://www.erlang.org/user.html, namely 'bucket_grid-1.0' and the older 'gridfile-1.0'. Both are only partially correct, and never did scale well. The most buggy part is previous/next (where I also bit off more than I could chew.) Perhaps the best option would be to start over...
I guess when trying to use Erlang for this type of thing, you have to determine what level of scalability and performance is "good enough".
> -----Original Message-----
> From: owner-erlang-questions@REDACTED
> [mailto:owner-erlang-questions@REDACTED]On Behalf Of Marc
> van Woerkom
> Sent: den 9 juni 2004 11:07
> To: erlang-questions@REDACTED
> Subject: Storing/Accessing stuff in a big terrain map
> I would still like suggestions how to store stuff in a
> large terrain map in a nice way in Erlang.
> That is not that obvious, I take frome the mail below,
> where some Haskell guy simply interfaced to C.
> --- die weitergeleitete Nachricht folgt ---
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