> Date: Wed, 9 May 2012 18:00:07 -0300
> From: Etienne Tourigny <etourigny....@gmail.com>
> Subject: [Qgis-developer] show grid on map canvas (similiar to grid
>         used in composer) - strategy?
> To: qgis-developer <qgis-developer@lists.osgeo.org>
> Message-ID:
>         <ca+txyvpd-5vhoycx4uhio9x416hkx9zgeq5ennnqvadp0l9...@mail.gmail.com>
> Content-Type: text/plain; charset=ISO-8859-1
> 
> Hi all,
> 
> I would like to add support to draw a grid on the map canvas, in a way
> similar to what is done in the map composer (although perhaps without
> the annotations on the borders).
> 
> What should be the approach used?
> 
> 1) plugin or core?
> 2) rubberbands or basic plot functions triggered after mapCanvas update?
> 
> I think both drawing strategies are possible using a plugin.
> 
> It would be best to write in the core, assuming there is sufficient
> interest in this, but it will take time to trickle down to the stable
> version (an argument for making it a plugin).
> 
> I know the current workaround is to create a vector grid with ftools,
> but that is a little clunky.
> 
> Any thoughts?
> Etienne

Hi,
I'm not a developer, so this might be a crazy and unnecessary idea, but would 
it be feasible to create a graticule _provider_?

This approach would mean that like grids created with ftools, the grid would be 
created as a layer, but it wouldn't be file based and its extents would 
automatically update.

Unlike the approach used in the composer, this would mean:
- digitising tools could snap to the grid lines.
- the identify tool could identify the grid lines.
- the layer could be used for analysis (e.g. you might want to use it to split 
vector layers).
- symbology and feature labelling could work just like other vector layers.

If this was to actually replace the grids in the composer, some improvements to 
feature labelling would be needed.  Some of these would probably be good to 
have anyway, e.g. an option to label both ends of a line, and an option to 
align labels horizontally or vertically on the page, rather than N-S or E-W.  I 
guess the difficult one would be providing a way to display labels outside the 
map frame...

Regards,
Alister_______________________________________________
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