Path: utzoo!attcan!uunet!mcsun!sunic!tut!tukki!sakkinen
From: sakkinen@tukki.jyu.fi (Markku Sakkinen)
Newsgroups: comp.databases
Subject: Re: More on image databases
Message-ID: <2955@tukki.jyu.fi>
Date: 7 Feb 90 11:19:53 GMT
References: <15498@orstcs.CS.ORST.EDU>
Reply-To: sakkinen@jytko.jyu.fi (Markku Sakkinen)
Organization: University of Jyvaskyla, Finland
Lines: 54

In article <15498@orstcs.CS.ORST.EDU> curt3028@oce.orst.edu (Curt Vandetta) writes:
> [..]  I'm working for a 
>  professor who is doing satellite image processing, and I've 
>  put together a database to keep track of his images.  I've found
>  that the relational model works very well for keep track of 
>  the properties of each image, [...]
> ...
>  The problem is that I have a byte stream that is 262.144K (the images
>  are 512 x 512 x 8bits, some day to be 24bits deep) which is much to
>  big for a single column, and a head ache to try to maintain multiple
>  columns (like 512 columns one for each raster line).  
>
>  The idea of compressing the image before I store it brings me to the
>  problem of variable length columns [...]
> ...
>  query like "Give me all of the tiles e (where e is say the tile that
>  has the San Francisco Bay in it) where the average temperature for the
>  bay is above 55 degrees"  Don't let the "average part" confuse the
>  issue here, that was just an example, the query could be on say
>  pixel 10245, so it would "every tile with pixel 10245 greater than
>  134 (a byte value that represents 55 degrees)".
> ...

Here comes a surprising comment from someone who firmly believes OO databases
to be the way of the (not too distant) future --
The purposes mentioned do _not_ seem to necessarily require an OO approach.
There is no great need for data abstraction and encapsulation,
which are among the prime concerns of object orientation.
Rather, the "everything is equally visible" principle of the relational
model would seem to apply quite well - some reservations must perhaps be made
if data compression is considered.

In consequence, some of the extensions of the relational model might
be pretty suitable for your kind of problem, because they can handle arrays.
One school is called NF^2 (for non-first normal school): for instance
the work at the IBM Heidelberg Scientific Center in Germany (AIM =
Advanced Information Management). Then there is Postgres from Berkeley,
which I believe was recently announced to be available over the net
(anonymous FTP?).

>  And all of this doesn't even bring be to issue of viewing each image,
>  but that's a topic for another news group :-)
> ...

That could be more natural in an OO system, but not impossible
to add to an extensible system like Postgres either.

Markku Sakkinen
Department of Computer Science
University of Jyvaskyla (a's with umlauts)
Seminaarinkatu 15
SF-40100 Jyvaskyla (umlauts again)
Finland
          SAKKINEN@FINJYU.bitnet (alternative net address)