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pcplantdb - Re: [pcplantdb] [synthesis][30][12.11.04]

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  • From: Plants For A Future <webmaster@pfaf.org>
  • To: Permaculture Plant Database <pcplantdb@lists.ibiblio.org>
  • Subject: Re: [pcplantdb] [synthesis][30][12.11.04]
  • Date: Sun, 12 Dec 2004 13:00:57 +0000 (GMT)

On Sat, 11 Dec 2004, Stephanie Gerson wrote:

4. 3-D Representation
Rich wrote, ÿÿPersonally I've never been too impressed with using 3D
representation, you tend to get a pretty cloud of dots. 3D searches can
be done in a 2D way (eg excel pivot tables) this might be a good way to
go.ÿÿ
Rich, can you please show us examples of what youÿÿre referring to?

Its quite difficu;t to give an written example of a pivot table,
i'd recomend that folks start up excel create a few bits of data and use
the pivot table wizzard.

Basically a pivot table is an interactive
way of summerising a lot of data in a 2D
table.

The data is arange as a table and their are drop down lists which let
the user select what the want displayed in the rows and what they want
displayed in the columns. The pull down capabilities make it easy to
quickly change the data which is displayed.

Bellow is something I pinched from a Slashdot discussion

A simple example of pivot tables (Score:5, Informative)
by sjbe (173966) on Friday November 19, @05:28PM (#10869920)
The best way to understand pivot tables is probably by example. Lets say
we have a spreadsheet with four categories of data: Country, Continent,
GDP, and Population. These are listed in columns, with corresponding
entries next to each other like so (apologies for bad formatting):

Country Continent GDP Pop
China Asia $1000 1,000,000,000
Japan Asia $5000 100,000,000
USA North Am $15000 280,000,000

Then lets say we are interested in finding the population of countries
on our list which a located in asia. Pivot table provide a fast way to
sort data as well as conduct simple mathematical operations on lists of
data.

Using a pivot table I could end up with a matrix that looks like:

Continent Country Population
Asia China 1,000,000,000
Japan 100,000,000
North Am USA 280,000,000

Now I have the data sorted by continent. If I decide I'm not interested
in population but instead in GDP, it is a simple drag and drop operation
to get a table like:

Continent Country GDP
Asia China $1000
Japan $5000
North Am USA $15000

Basically pivot tables let you explore lists of data very quickly and
efficiently. If you deal with lists of data regularly like I do, they
are one of the most indespensible features in a spreadsheet. Excel has
the best ones I've used but most modern spreadsheets have some version
of them.


Weka http://www.cs.waikato.ac.nz/~ml/
and Orange http://magix.fri.uni-lj.si/orange/
Quantix ttp://www.quantrix.com/
might be worth a look.

Rich


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