Frankly, I'd go for bar charts: multiple pie charts are very difficult for
end-users (particularly bosses who want the impossible) to visualise.
Kent: you have my sympathies: I, too, have a boss who has unworkable ideas
quite often, and I reckon that the first thing I routinely say when he comes
up with a new demand is "it can't be done: what is the simplest
diagram/map/graphic we can get away with?" and we negotiate from there. He
gets what he wants, rather than what he asks for! Many managers are unaware
that the sheer quantity and density of data they demand means that the data
are not translated - nor translatable - into meaningful, useful information.
This is particularly true of maps, which can be very opaque to the
unsophisticated reader, despite the intuitive grasp of the concept of a map
that most people have, or think they have.
Not much help with the problem, but maybe a strategy for the future!
Another possible avenue ... how about using a data-simplification technique
in a stats package (I use SPSS) such as factor analysis to tease out three
underlying factors (call them Factors A, B & C) that may be used to explain
the multiplicity of variables you have. Each subject will have a value of
0.0 - 1.0 for each of the three factors: colour each point marker with RGB
according to the three factors: red component for factor A, green component
for factor B and blue component for factor C. For a legend, use the 3 'pure'
colours and the 3 complementary colours. You'd need to use MapBasic, but
that should be easy enough.
It's just a thought - I've never actually tried it. If it works, I quite
fancy having a technique named after me - it would impress my kids no end
Season's greetings to all
Graham O'Brien!
----- Original Message -----
From: Dr Rajeev saraf <[EMAIL PROTECTED]>
To: W. Kent Treichel <[EMAIL PROTECTED]>; Mapinfo List <[EMAIL PROTECTED]>
Sent: Friday, December 24, 1999 3:24 AM
Subject: Re: MI Dot Density custom symbols
>
> What you may do is:
> Add 10 fields to planning district that stores the total number of
clients
> in each program. Now you can create a pie chart or bar chart to show the
> numbers for each zone in each program.
> --
> Rajeev saraf
> -----Original Message-----
> From: W. Kent Treichel <[EMAIL PROTECTED]>
> To: Mapinfo List <[EMAIL PROTECTED]>
> Date: Friday, December 24, 1999 5:22 AM
> Subject: MI Dot Density custom symbols
>
>
> >Merry Christmas!
> >I am trying to make a map. I have about 8000 addresses that I have
> >geocoded in St. Paul, MN. Most of them are clustered in certain parts
> >of the city. My boss wants one, and only one, map that shows where the
> >clients live what type of program they are involved in and where the
> >programs are located in the city. There are approximately 70 programs.
> >I tried individual values but the map is not legible. Even if I
> >collapse the programs down to 10 with ten corresponding symbols that are
> >legible, the addresses are so close together in certain areas that the
> >symbols would be illegible. (If I had a large format plotter, this
> >might not be a problem, but the best I can do is 11x17.) I liked the
> >look of the dot density maps. It provided a good graphical shot of what
> >part of the city our clients come from. Now the question. How can I
> >combine the best of individual value with the dispersed representation
> >of dot density? And as long as I'm asking for the moon, how can I
> >ensure that they don't overlap with each other?
> >The final product would look something like this; a map of the city with
> >planning districts (17), within each planning district a certain number
> >of circles, squares, stars etc, representing the corresponding number of
> >clients in a particular program.
> >Negative responses appreciated as well, so I can start trying to figure
> >out a different strategy.
> >Respectfully submitted,
> >Kent
> >--
> >W. Kent Treichel
> >Wilder Research Center
> >1295 Bandana Blvd N. Suite 210
> >St. Paul, MN 55108
> >(651) 647-4636
> >______________________________
> >
> >We sleep safely in our beds because
> >rough men stand ready in the night
> >to visit violence on those
> >who would do us harm.
> >
> >George Orwell
> >----------------------------------------------------------------------
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> >"unsubscribe MAPINFO-L" in the message body, or contact [EMAIL PROTECTED]
> >
>
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