# Re: Mapping question...

• Subject: Re: Mapping question...
• From: Paul van Delst <paul.vandelst(at)noaa.gov>
• Date: Mon, 11 Jun 2001 12:01:54 -0400
• Newsgroups: comp.lang.idl-pvwave,comp.graphics.visualization
• Organization: CIMSS @ NOAA/NCEP
• References: <3b24e6b1@news.ColoState.EDU>
• Xref: news.doit.wisc.edu comp.lang.idl-pvwave:25298 comp.graphics.visualization:17613

```Guillaume Dargaud wrote:
>
> For lack of a better place, I'll ask it here even though it is not IDL
> specific (but I will probably implement it in IDL).
>
> I need to make maps of the world in a special way (I don't even know what
> this is called, so if anybody can provide me with a keyword...)
> Say you have a quantity of rain per sq degrees and you want to enlarge the
> surface area of places where it rains a lot and shrink the surface area of
> dry places... You end up with a tiny sahara, but large tropical zones...
> How would you go to do something like that...?
> I have seen it done before, but don't know what this kind of mapping is
> called.

It doesn't sound like it will produce an easy to understand map, but what would I know.
FWIW, I'm always suspicious of maps/graphs that use area as a graphing dimension since
area is a squared quantity and usually the number used to calculate the area is not scaled
for this leading to a biased plot that emphasises the larger values (like when graphs use
different sized circles and/or squares to represent a 3rd dimension in a 2d plot.).

cheers,

paulv

--
Paul van Delst           A little learning is a dangerous thing;
CIMSS @ NOAA/NCEP        Drink deep, or taste not the Pierian spring;
Ph: (301)763-8000 x7274  There shallow draughts intoxicate the brain,
Fax:(301)763-8545        And drinking largely sobers us again.
Alexander Pope.
```