Subject: [Thuban-list] sized point data

From: "Moritz Lennert" <[email-masked]>
Date: Wed, 20 Oct 2004 00:12:53 +0200 (CEST)

Hello,

I just browsed through the archives of the development list and discovered
that sized point data has been implemented. This is extremely good news !
(and I hope that you did get paid for it ;-) )

I just did a fresh cvs checkout and tried it and it looks promising.
Obviously, the inclusion of point size in the classification would make
life even more beautiful...

And to push you all further to new heights: how about a combination of
point size and point color representing two separate classifications (ex:
point size=current population size of a city and point color=population
growth rate between 1990 and now). Would this be very complicated ?

But before I give the impression of ingratitude, I would like to thank you
all  (and especially Jan) for this great new feature !

Moritz

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From: Jan-Oliver Wagner <[email-masked]>
Date: Wed, 20 Oct 2004 07:48:01 +0200

> (and I hope that you did get paid for it ;-) )

unfortunately not, I was just sitting in the train with my laptop ...

> life even more beautiful...

hm, actually it is considered by the classification.

> growth rate between 1990 and now). Would this be very complicated ?

I will move my mind about this feature.
I added this to the Roadmap feature proposals anyway since it is
definitly interesting.

> all  (and especially Jan) for this great new feature !

Hope it helps you for the case you describe some months ago.

Best

	Jan
-- 
Jan-Oliver Wagner               http://intevation.de/~jan/

Intevation GmbH                      http://intevation.de/
FreeGIS                                http://freegis.org/

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From: "Moritz Lennert" <[email-masked]>
Date: Wed, 20 Oct 2004 09:44:44 +0200 (CEST)

> hm, actually it is considered by the classification.

Either I didn't see how, or I was not clear enough. What I meant was that
presently it seems that I have to set the size by hand. I can't just tell
thuban that I want each point to be displayed automatically in a size that
is proportional to a given column value (this could be a special case of
"unique values" but where the classification does not result in a color
ramp, but in a "size ramp"). The former is ok if I have a few sites or
only few different sizes, but if I have several hundred "sites" then the
latter becomes necessary.

For the implementation of the proportionate size it would also be
necessary to be able to determine a scale factor, i.e. a constant by which
to multiply the size of all sites in order to adapt the sizes to the map.

> I added this to the Roadmap feature proposals anyway since it is

Actually if the "automatic" size is implemented seperately from the
classifier, and the classifier remembers the sizes, then it would be
possible to reclassify the different point (colors) according to any given
column. At present, using the iceland_sample_size session, when I
reclassify the cultural landmarks, they all go back to the same size and I
have to reset the size manually. If the classifier could remember the
sizes (given either manually or through some automatic proportionate
mechanism, then the combination of sizes and colors should be no problem.

> Hope it helps you for the case you describe some months ago.

It does. We are getting closer to having something that I might be able to
sell to my colleagues.

Many thanks again (including to the Deutsche Bahn ;-)) !

Moritz