[Qgis-user] proportional symbols

[Goyo]

It seems to be a more common feature than I thought. Still I don't
understand the use if this (I think double size should mean double
population) but I guess I can live with the clutter.

Goyo

El lun, 27-10-2008 a las 23:21 +0100, G. Allegri escribió:
> 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
> >> > _______________________________________________
> >> > Qgis-user mailing list
> >> > Qgis-user at lists.osgeo.org
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> >
> >