AW: [mapserver-dev] RFC49: mapfile simplifications and symbologyenhancements

[Karsten Hoffmann]

Hi Thomas,

I’m not sure if I understand what you mean. 

I tried your proposition with Mapserver 5.2. But all circles have the same
size (43 pixel):

LAYER
  NAME        population
  TYPE         POINT
  STATUS    default
  DATA         Lan_point.shp
  CLASS
    NAME 'Population'
    STYLE
        SYMBOL 'circle'
        SIZE [poptotal]
        MINSIZE 18
        MAXSIZE 43
        OUTLINECOLOR 0 0 0
        COLOR 0 0 255
    END
  END
END

The sizes of the circles should vary depending on the number of habitants. I
don’t want to preprocess the population data. At the moment I calculate the
sizes of the circles by myself and write them in a new field (pop_size) in
the attribute table. 
The Style is then:

    STYLE
        SYMBOL 'circle'
        SIZE [pop_size]
        OUTLINECOLOR 0 0 0
        COLOR 0 0 255
    END

The population varies from around 5000 to 30000 habitants. The sizes of the
circles should vary from 18 to 43.

With a Chart-Layer it is very comfortable to define this:

PROCESSING "CHART_SIZE_RANGE=poptotal 18 43 5000 30000"

But I don’t want to have a pie chart with slices here just a simple filled
circle.

Best,
Karsten


-----Ursprüngliche Nachricht-----
Von: thomas bonfort [mailto:thomas.bonfort at gmail.com] 
Gesendet: Donnerstag, 4. Dezember 2008 12:18
An: Karsten Hoffmann
Cc: mapserver-dev Mailing List
Betreff: Re: [mapserver-dev] RFC49: mapfile simplifications and
symbologyenhancements

karsten, if I understant your request correctly, MapServer already has that:

STYLE
 SYMBOL "circle"
 SIZE [population]
 MINSIZE 3
 MAXSIZE 20
END

you'll probably want to preprocess the [population] in your data
request (to add steps, or scaling)

regards,
thomas

On Thu, Dec 4, 2008 at 11:45, Karsten Hoffmann
<khoffmann at igf.uni-osnabrueck.de> wrote:
> Dear developers,
>
> I would like to ask for another feature which could be perhaps included in
> this RFC.
>
> Since version 5.2 it's possible to bind the size of pie charts to an
> attribute (https://trac.osgeo.org/mapserver/ticket/2136):
> PROCESSING "CHART_SIZE_RANGE=itemname minsize maxsize minval maxval"
>
> This would also be useful for point symbols as simple diagrams without
> slices or bars. The idea is to have a symbol, let's say a filled circle or
> square, which varies continuously in size. The size is bound to an
attribute
> for example the absolute number of habitants of different countries.
>
> This would be a useful feature for thematic mapping. Is it possible to
> implement this?
>
> Best regards
> Karsten Hoffmann
>
>
> -----Ursprüngliche Nachricht-----
> Von: mapserver-dev-bounces at lists.osgeo.org
> [mailto:mapserver-dev-bounces at lists.osgeo.org] Im Auftrag von thomas
bonfort
> Gesendet: Donnerstag, 4. Dezember 2008 11:18
> An: mapserver-dev Mailing List
> Betreff: [mapserver-dev] RFC49: mapfile simplifications and
> symbologyenhancements
>
> Hi,
>
> Not sure if the changes warrant a full blown RFC, but as there quite a
> number of them I've regrouped them.
>
>
http://trac.osgeo.org/mapserver/browser/trunk/docs/development/rfc/ms-rfc-49
> .txt
>
> These changes are/were all in RFC45, but were extracted to keep things
> moving on as some of the stuff in rfc45 lacks funding in the near
> future.
>
> You can see it in action here on openstreetmap data:
> http://mapserverosm.s3.amazonaws.com/parisosm.html
> nothing that's impossible to do with the current mapfile keywords
> (except for polygon label placement, and thin lines thanks to
> fractional size/widths), but the mapfile maintainance and creation is
> greatly simplified, as e.g. roads are mostly defined with a single
> class whatever the scale (using a combination of sizeunits at the
> layer level, and min/max width and min/max scale at the style level)
>
> regards,
> thomas
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