Re: country borders on 2d-world

[Juhász P. <pet...@gm...>]

On Thu, 2015-10-22 at 00:17 -0500, Daniel J Sebald wrote:
> On 10/21/2015 07:02 PM, Valerio Schiavoni wrote:
> > Hello,
> > it is known that drawing a 2D map of the world is possible:
> > - http://www.gnuplotting.org/plotting-the-world-revisited/
> > - http://gnuplot.sourceforge.net/demo/world.html
> >
> > But, suppose that I want to:
> > - also show the country/nation/state borders and
> > - some of the country/nation/states need to be highlighted somehow (a
> > different filling color than plain white would be ideal)
> >
> > Ideally there would be several groups of country/nation/states sharing
> > the same filling colours
> >
> > Has anyone ever attempted at this ?
> > Suggestions ?
> 
> I've thought of doing such a thing:
> 
> http://sourceforge.net/p/gnuplot/mailman/message/26788631/
> 
> Although it isn't a type of plot I'd use in my field, it would be a 
> really nice feature given how common this type of geographical "plot" 
> with data points is today.  A command syntax is going to be the 
> difficult part.  Defining the maps is another issue.  What if boundaries 
> change?  Is there some type of universally accepted data format or 
> descriptive language for map boundaries these days?
> 
> Dan
> 

Two more issues that count against including high-resolution map data
into gnuplot itself:

- licensing
- data size

In more detail:

The first link in the OP refers to
http://www.naturalearthdata.com/downloads/ , where you can eventually
download datasets for continent, lake and country boundaries in three
different resolutions. It says that the dataset is in the public domain,
which means that it's fine if you want to produce maps with it on your
own, and it may be fine for inclusion into gnuplot (but IANAL).
The highest resolution dataset that includes country borders is >5 MB
compressed, which is comparable to the current size of gnuplot's binary
package.

There is also GSHHG, http://www.soest.hawaii.edu/pwessel/gshhg/ , which
is used by software packages such as GMT or IDL, however, its license is
LGPL, which is not compatible with gnuplot's license - or is it?
The entire package is above 100 MB which precludes its inclusion (but it
contains lower resolution datasets that are likely smaller).


> "Is there some type of universally accepted data format or descriptive
> language for map boundaries these days?"

Universally accepted? I don't think so. 
However, there are many competing, widely recognized formats, ESRI
Shapefile being perhaps the most used.


Peter