[GRASS-dev] C replacement for d.vect.thematic

[Moritz Lennert]

On 29/12/07 18:25, Michael Barton wrote:
> v.class is similar to r.stats in what it does. You might want to 
> consider naming it v.stats to make it easier for users to grok this 
> similarity. I assume that v.class will also output to a text file?

It prints to standard output so you can redirect to a text file. But I'm 
not sure I see how it is so similar to r.stats... Will think about it.

I'm actually also thinking about modifying the function to take 
arbitrary float vectors, and not dbCatValArrays, thus allowing the 
classification of any data, not only vector, and also avoiding to carry 
around a whole dbCatValArray structure where only the actual values are 
needed.


> I'd rename the thematic modules to d.thematic.area, d.thematic.point, 
> d.thematic.legend. This lets them easily group in any alphabetical 
> listing and clearly associates them. It also uses consistent GIS objects 
> for the subname of each (i.e., point instead of symbol, because points 
> and areas are the objects being displayed). 

ok.

> 
> What about lines? Can v.class classify lines and boundaries, 
> and d.area.thematic  display them by color and thickness? Or will that 
> need another module?

For me lines and points are symbols and I put them together into 
d.symbol.thematic, but I guess we should split them.

> 
> Finally, is there any way to make use of color table capabilities, like 
> used with r.colors? This would allow a lot of nice displays more easily 
> than having to list colors.

This would be great. I have also been thinking about a way to integrate 
the ColorBrewer palettes. Don't know their exact licensing, but I think 
uDig has integrated them, so should be possible. This could then lead to 
a g.colorbrewer which allows you to chose a palette according to 
different criteria and then output it for d.thematic or other modules.

I think it would also be great to have a GUI colorchooser module, but I 
think this will have to be a GUI element as IIUC g.parser does not allow 
for color buttons to change according to the color you chose and thus 
you cannot see all the colors you chose side by side (one of the most 
annoying things in QGIS IMHO).

So, yes, lot's left to do...

Moritz