[Qgis-developer] Using PostGIS on a slow connection

[Martin Dobias]

Hi Paolo

On Mon, Mar 3, 2014 at 7:18 PM, Paolo Cavallini <cavallini at faunalia.it> wrote:
> Il 27/02/2014 03:17, Martin Dobias ha scritto:
>
>> Paolo: make sure you have render caching turned on. Deactivating (and
>> activating again) a layer should be immediate. Of course, if you pan
>> the map or zoom in/out, everything will be re-rendered.
>
> Hi Martin,
> thanks for this. It helps, but my question remains: why should we reload
> data, just to *disable* a layer from the legend?

In order to remove a layer from a map, you simply need to redraw the
whole map _without_ that layer. The render caching helps by recording
image of each layer separately, so removing a layer from legend
requires just combining the rendered images together without the
removed one - without having to redraw also other layers. Maybe we
should just make render caching default.

Regards
Martin