[Gvsig_english] SQRT and proportional symbols

[Simon Cropper (Botanicus Australia Pty Ltd)]

Juan Lucas,

You map looks really good.

I was thinking however that if your NUMERIC_FIELD represents population 
size
assuming the circle area in the legend field is calculated using radius 
wouldn't
NEW_FIELD = SQRT(NUMERIC_FIELD/PI()) give you a better estimate?

Cheers Simon

Simon Cropper
Botanicus Australia Pty Ltd
PO Box 160, Sunshine, Victoria 3020.
P: 9311 5822. M: 041 830 3437.
mailto: scropper at botanicusaustralia.com.au 
<mailto:scropper at botanicusaustralia.com.au>
web: www.botanicusaustralia.com.au <http://www.botanicusaustralia.com.au>


On 3/02/2010 4:57 AM, Juan Lucas Dominguez Rubio wrote:
> Hello.
> If your vector layer has a numeric field, you can do this:
> - Add a new field of type DOUBLE
> - Use the function SQRT in the field calculator so that
> NEW_FIELD = SQRT(NUMERIC_FIELD)
> - In the symbology dialog, choose 'proportional symbol' with your 
> favorite settings.
> This is what you'll get:
> http://www.prodevelop.es/files/fm/public/downloads/documents/screenshots/gvsig_desktop/ita.html
> Circle area (not diameter) is proportional to population.
> Regards,
> Juan Lucas Domínguez Rubio
> ---
> Prodevelop SL, Valencia (España)
> Tlf.: 96.351.06.12 -- Fax: 96.351.09.68
> http://www.prodevelop.es <http://www.prodevelop.es/>
> ---
>
>
> _______________________________________________
> Gvsig_internacional mailing list
> Gvsig_internacional at listserv.gva.es
> http://listserv.gva.es/cgi-bin/mailman/listinfo/gvsig_internacional
>