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| GeoCommunity Mailing List |
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| Mailing List Archives |
| Subject: | Re: GISList: ArcGIS: gird problems |
| Date: |
08/24/2003 07:55:01 AM |
| From: |
GISex* Technologies |
|
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> Julia Reisemann wrote:
>
>> Hi,
>>
>> does anybody have an idea how to deal with a grid that has an integer
>> value but thinks it is a floating point. Is there something like a
>> build vat in ArcGis 8?
>>
>> Hm, grids with personality disorders, what will be next?
>>
>> Julia
>
> Hi Julia & all,
>
> a technologist's reply: Given the many personalities numbers and grids can
> convey :-), a promising approach is to make software intelligent enough to
> handle all data types and their arithmetics. In conjunction with a dynamic
> query
> language (yes, I am a database guy) you can teach grids then to behave in
> ballroom as well as in the street.
>
> Let me do the small experiment in the rasdaman query language, rasql.
> Assume
> grids over float (or double) numbers.
> - "my grid with original data" (returns a float grid in our case)
> select grid
> from MyGridCollection as grid
>
> - "A 32-bit integer grid from my float grid" (returns an int grid)
> select (int) grid
> from MyGridCollection as grid
>
> - "A map of the rounding error" (the result is a grid where each pixel
> holds the
> deviation)
> select grid - (int) grid
> from MyGridCollection as grid
>
> - "Was there any rounding error at all?" (The result is one single boolean
> value)
> select some_cells( grid - (int) grid != 0 )
> from MyGridCollection as grid
>
> Of course a regular user would not be bothered with such syntax, that is
> normally hidden in the client code. On the other hand, based on a query
> language
> someone with just intermediate familiarity can handle surprise attacks
> like
> Julia's situation in a few minutes.
>
> So, Julia, I'd argue for tools that respect individuality - if you
> consider
> complex numbers (like for spectral imagery), then you even get split
> personalities... :-)
>
> Regards,
> Peter
> --
> Dr. Peter Baumann, Executive Director
> rasdaman GmbH
> WWW: http://www.rasdaman.com/
> Email: mailto:baumann@rasdaman.com
> Dialup: voice +49-89-67000146, fax +49-89-67000147, mobile +49-173-5837882
> "A brilliant idea is a job halfdone."
>
>
>
>
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--
The meeting of two personalities is like the contact of two chemical
substances: if there is any reaction, both are transformed.
Krishan Sharma, Ph.D. (USA)
www.gisextechnologies.com
www.kksharma.org
Mobile: 982-112-8409
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