AW: [mapserver-dev] RFC49: mapfile simplifications andsymbologyenhancements

[Brent Fraser]

Steve,

  Perhaps a compromise would be to allow some simple arithmetic expressions (like the ones in the FILTER keyword?), such as:

    SIZE  ( 18 + [poptotal] * (( 43-18)/(5000-30000))  )

In my case, I've got ANGLEs in a shapefile (ok, 13,000 shapefiles) as "standard" angles (0=x-axis, + is ccw) but Mapserver likes azimuths (0=y-axis, + = cw).  I'd rather not add another field to the shapefile, to minimize the data management problems.

Brent Fraser


Steve Lime wrote:
> MapServer's interpretation of size through an attribute binding is
> literal. That is, the value
> in the column is used as the size in pixels. Since you set a max scale
> it makes sense you
> see all size 43.
> 
> In that case your suggestion makes sense although I'm not sure the best
> way to implement.
> 
> I don't think strictly following the charting syntax makes sense since
> we'd then have two ways
> to bind attributes which would get confusing. Any ideas?
> 
> Steve 
> 
>>>> "Karsten Hoffmann" <khoffmann at igf.uni-osnabrueck.de> 12/04/08 5:59
> AM >>>
> 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
>>> 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
>> _______________________________________________
>> mapserver-dev mailing list
>> mapserver-dev at lists.osgeo.org
>> http://lists.osgeo.org/mailman/listinfo/mapserver-dev
>>
>>
> 
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