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| GeoCommunity Mailing List |
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| Mailing List Archives |
| Subject: | RE: GISList: Multi-Criteria&GIS |
| Date: |
05/08/2002 07:01:56 PM |
| From: |
Dimitri Rotow |
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> I am working on a project for selecting the best location for schools
> under certain criteria .I am using ArcView and I would like to get any
> software that deal with Multicirteria and GIS in the same time where it
> is possible to get the code for these software So I can make some
> developments on it if necessary . Does any can help ?.
>
Depends what you mean by "multicriteria" and "code."
Manifold includes a neurofuzzy inference engine that is used via the
Decision Support System. This allows people to ask questions (query) the
GIS using many criteria at once where the criteria can be flexible (fuzzy),
with automatic tradeoffs. It's a wonderful system for location studies.
For example, suppose you want to find a new house that is in a "good" school
district but "not too far" a commute from work. In traditional SQL
multicriteria queries, one chooses fixed threshold values that define a
"good" school and a "not too far" commute. For example, you might say a
"good" school was one with an average math SAT of 600 and above and a "not
too far" commute was 10 miles.
The problem with the classic rigid approach is that it rejects the sort of
tradeoffs people do in real life. For example, it would reject a house with
a commute of 10.5 miles even if it put you into a school district with an
average math SAT of 715, a tradeoff most people would willingly make (or, at
least want to consider). The practical utility of "fuzzy" logic
multicriteria searches is that such tradeoffs are automatically
accomplished.
In the past, doing decision support by fuzzy logic searches was difficult
because the tools were so perversely difficult to use. It was as if one had
to take an advanced study course just to write a simple query. The Decision
Support System in Manifold takes a more practical approach of providing
presets for the most common wishes people have so that multicriteria fuzzy
searches can be a simple point and click affair. By using Active Columns or
Intrinsic Fields you can include spatial relationships within a DSS query as
well.
You can also use the neurofuzzy engine in a more programmatic way by using
the fuzzy SQL extensions in Manifold, writing SQL code, or in a simpler way
by clicking on a record and choosing "More Like This". In the latter case,
the system knows what fields are visible and how they compare in the record
you clicked to the data set at large and so it automatically constructs and
launches a neurofuzzy query to find more records like those you want. Like
magic, records that are more like what you want bubble up to the top.
For readings in the Decision Support System see
http://exchange.manifold.net/manifold/manuals/5_userman/mfd50Introduction_to
_Decision_Support.htm
and
http://exchange.manifold.net/manifold/manuals/5_userman/mfd50Rank_Columns__D
ecision_Support_S.htm
The SQL extensions (very technical) are at
http://exchange.manifold.net/manifold/manuals/5_userman/mfd50Manifold_SQL_Ex
tensions.htm
"More Like This" is at
http://exchange.manifold.net/manifold/manuals/5_userman/mfd50More_Like_This.
htm
Since ArcView is utterly clueless about modern database ideas like
neurofuzzy inferencing built into the GIS, I think the simplest way to use
this in your project would be to save your data as shapefiles, do all the
sophisticated multicriteria stuff in Manifold, and then save the Manifold
results as shapefiles should you need to share them with people who are
forced to continue using ArcView.
It's true that Manifold is an extra $245 cost, but there is nothing else in
either the database or GIS world that can give you such powerful
multicriteria fuzzy searching ability for anywhere near that price.
Manifold includes the ability to write your own code as well (Visual Basic
scripting, Javascript, PERL or Python, or in VB or VC++, etc.) if you wish
to pursue your own developmental efforts.
Cheers,
Dimitri
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