[Qgis-developer] show grid on map canvas (similiar to grid used in composer) - strategy?

[Ramon Andiñach]

On 11/05/2012, at 8:22, "Alister  Hood" <Alister.Hood at synergine.com> wrote:

> vector operations on a grid.  And I guess the digitising tools would be disabled for these layers.  But people do treat grids as features for geoprocessing,.
> 
>>> interesting approach might be to use QgsPluginLayer class, but IMHO a
>>> grid is not even a layer... e.g. does it make any sense to draw some
>>> other layers on top of a grid?
> 
> Certainly not usually, at least for printing, although I can imagine using a grid of alternating filled gray and white squares under the map layers, rather than grid lines over the map layers.  
> I can also imagine if someone was working with point and line layers and unfilled polygon styles they might move these layers above the grid to make it easier to see them.  
> Anyway, it would certainly make sense in some cases to have more than one grid "layer", to be able to symbolise them differently (which implies being able to control which one of them is above another) and turn them on and off independently.  Creating them as layers would make this simple.
> 
>> I guess it makes more sense to draw the grid on top - are there any
>> uses to draw the grid below the layers? In any case, a simple
>> (top/bottom) selector would suffice.
> 
> I doubt there are many cases when somebody would want grids below the layers, but I wouldn't rule it out entirely.
> But I do think people would want grids below feature labels and diagrams (other map decorations are above these), and below map annotations (other map decorations are below these, although I think that they probably shouldn't be).

+1

I would definitely want it below labels and annotations at least; and I can also easily think of situations where I might want to move it below other layers. 

-ramon.