[GRASS-dev] Re: [Qgis-developer] Re: Value tool plugin makes QGIS crash

[Radim Blazek]

On Mon, Mar 28, 2011 at 9:38 AM, Hamish <hamish_b at yahoo.com> wrote:
> Radim wrote:
>> If there are 10 maps open in QGIS, it starts 10000 executables
>> in about 1 second. That is probably a bit slow.
>
> maybe a little :)
>
> I do not suggest this as a correct solution, but fyi r.what can
> take multiple input maps in a single call.

That is impossible in QGIS, where the functionality is implemented in
data providers, one per layer, which know nothing about other layers.

> It can also take multiple input coords in a single call, so you can at least
> queue you queries into bigger sized chunks if you like, which
> would ease the pain a little.

Maybe, but probably source of other problems, because it has to be
implemented in GRASS provider, and that means to add a little delay to
find if there are more values requested and that is not desired for
all tasks.

BTW the Value Tool with WCS via GDAL or WMS in QGIS (currently
disabled right?) could also be interesting, anybody tested? Does GDAL
WCS cancel running requests if another comes? Does it keep list of all
opened requests with an id?

> as a long term solution, would a from-scratch LGPL native GDAL
> driver help? ... Possible Summer of Code project for someone?

Do you mean de facto new GRASS raster library? Thread safe, exceptions
support etc... That could help.

Radim