[Qgis-user] proportional symbols

[G. Allegri]

It's very strange to me that it seams so strange to have proportional
point size symbology on the base of attributes values.
It's a basic feature of cartography...

Some example references I can give:
http://mapserver.gis.umn.edu/docs/howto/cartosymbols/#scaling-of-symbols
http://demo.mapfish.org/mapfishsample/1.0/examples/geostat/proportionalSymbols.html
http://www96.reliefweb.int/tools/details/geospatial-analysis/symbols-and-markers

2008/10/27 Goyo <goyodiaz at gmail.com>:
> OK I read the ticket and I think I've got the point now. First of all
> you'll want to know that the lower size limit is gone in 1.0 but I don't
> think you're going to get good looking results with your data anyway.
>
> So you want to tell the sizes for maximum and minimum field values
> (whatever they are) and get the size for any value computed by linear
> interpolation.
>
> To be honest I don't see this useful enough (in general) as to justify
> the additional clutter in UI. On the other hand that's the way colormaps
> are handled in rasters, more or less.
>
> Just some thoughts.
>
> Goyo
>
> El lun, 27-10-2008 a las 21:49 +0100, Goyo escribió:
>> Hi Giovanny,
>>
>> it scales the symbol size, not the attribute values. Since your
>> attribute values are big you're getting big symbols.
>>
>> Goyo
>>
>> El dom, 19-10-2008 a las 21:15 +0200, G. Allegri escribió:
>> > I migrate here a discussion started in a ticket
>> > https://trac.osgeo.org/qgis/ticket/960
>> >
>> > I change the question asking the following: how to make proportional
>> > symbols, i.e. with the size based on a certain attribute?
>> > I thought I should use the "Area scale fields" in the Properties
>> > window. It does the work, but it doesn't scale the sttribute values,
>> > so if the they are "big" the symbols overlay each other even covering
>> > the entire screen.
>> >
>> > I show two images about this:
>> > Property dialog: http://www.geospatial.it/allegri/property.png
>> > Result: http://www.geospatial.it/allegri/graduated.png
>> >
>> > I've used the lower allowed "Dimension" (=3)...
>> >
>> > Am I using a tool that wasn't supposed to do this work? Or am I using
>> > it in the wrong way?
>> >
>> > Giovanni
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>
>