[mapserver-dev] MapServer pie chart enhancements

[thomas bonfort]

Hi Tamas,
How would you express this in a pseudo-generic way inside the
processing keys? Are there any other functions that would make sense
here?

--
thomas

On Wed, Apr 11, 2012 at 20:14, Tamas Szekeres <szekerest at gmail.com> wrote:
>
> Hi Devs,
>
> One of our client requires an addition which could provide nonlinear
> function to visualize the size of the pies depending on the source
> attribute. Currently we can specify the chart size as follows:
>
> PROCESSING "CHART_SIZE_RANGE = itemname minsize maxsize minval maxval"
>
> This can provide the size as linear function of the item value. As an
> enhancement we would like to add further kind of functions (like square root
> or logarithm) to enhance the visual appearance (see the images attached).
>
> This addition could be implemented by introducing a new processing option
> (like: CHART_SIZE_FUNCTION ) and by adding a switch to the size calculation
> in mapchart.c.
>
> For example with the square root function we could use:
>
> diameter=MS_NINT(
> mindiameter+
> (sqrt((diameter-minvalue))/sqrt((maxvalue-minvalue)))*
> (maxdiameter-mindiameter));
>
>
> What do you think about this change?
>
>
> Best regards,
>
> Tamas
>
>
>
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