Chloropleth maps with Mapserver

[Jason Pickering]

Hi Bill,
Well, the end maps are more or less the same. I think the best
examples of what I would like to do can be found at the KIDS website.

http://kids.fao.org and then under "Application Examples".
Another good example is at
http://www.fao.org/landandwater/agll/agromaps/interactive/index.jsp

I am not starting with individual points (well, maybe but the data has
already been aggregated).

The question for me is whether it would be easier to modify KIDS (also
open source) or Mapserver to accomplish what I would like to be done.
I agree, that it seems that it in principle should be able to be
accomplished with Mapscript. It seems less obvious to me how to
implement this functionality in KIDS, as it doesn't have the same sort
of scripting support as Mapserver. I agree that there may be a way to
do it, but I thought if someone has proven that it can be done, it
would be good to start there instead of coding from scratch.

I will checkout the developers mailing list as well to see what is
there. Thanks for the tips.

Best regards,
JPP






On 10/2/05, Bill Binko <bill at binko.net> wrote:
> I assume you mean Choropleth Maps like this article suggests:
>
> http://www.teachingideas.co.uk/geography/chlormap.htm
>
> Are you (like the article) starting with points and you want to group
> them?  That is, you want the user to be able to specify how many groups to
> create, but there is underlying data?
>
> There may be a way to do this in Mapscript.  Also, you might find
> gdal_contour of value (or something similar).
>
> Bill
>
> On Sun, 2 Oct 2005, Jason Pickering wrote:
>
> > I am currently evaluating the capabilities of MapServer to retrieve
> > data from a Postgresql database and display it on a chlorpleth map.
> > For instance, I have data like:
> >
> > Area      IndicatorValue
> >
> > Area 1     10
> > Area 2    20
> > Area 3  15
> > Area 4  20
> > etc etc
> >
> > Each region will be represented by a color, depending on what the
> > value is in the "IndicatorValue" column. The users need to be able to
> > select (dynamically) how many color regions will be displayed on the
> > map, and what the value range of each color is.
> >
> > I have searched high and low through the archives, and Google, but
> > can't seem to find a definitive answer, or better yet, and example of
> > how this can be done with Mapserver.Any pointers would be most
> > welcome.
> >
> > Best regards,
> > JPP
> >
> >
>