[GRASS-dev] Rendering of vector layers can be slow

Hi,

At the moment I am fixing and quality checking relatively larger vector datasets with some 100k areas, of which some are quite complex (sea area / coast line). That requires visual inspection of the data and thus repeated rendering at different scales.

In this context I am struggling with rendering speed in GRASS 7.0.4. I am working on a relatively powerful server with local data in native GRASS format.

In comparison, QGIS on my local laptop renders the same data from PostGIS significantly faster, even when fetched through a WLAN connection…

Any possibilities to speed up rendering of vector maps?

Cheers

Stefan

On 08/08/16 11:27, Blumentrath, Stefan wrote:

Hi,

At the moment I am fixing and quality checking relatively larger vector
datasets with some 100k areas, of which some are quite complex (sea area
/ coast line). That requires visual inspection of the data and thus
repeated rendering at different scales.

In this context I am struggling with rendering speed in GRASS 7.0.4. I
am working on a relatively powerful server with local data in native
GRASS format.

Vector rendering speed has been an issue and has been discussed before, a long time ago [1, 2], but I don't remember if there was much follow-up in terms of changing d.vect. The issue was mentioned again later [3]. Also see the debate in [4], but this was not explicitely about vector rendering.

In comparison, QGIS on my local laptop renders the same data from
PostGIS significantly faster, even when fetched through a WLAN connection...

AFAIK, QGIS now has multithreaded rendering. I don't know if this creates the difference. Also watch out: QGIS starts rendering parts of the layer very quickly, but you have to compare the time it takes for both to render the entire layer.

Any possibilities to speed up rendering of vector maps?

Maybe some of the ideas Glynn advanced in the response to [2] are still relevant. I don't think there have been any changes related to these ideas to lib/gis/plot.c since that discussion.

I agree that this would probably be of use, but I guess it never has been an itch strong enough to provoke those who have the knowledge into action. :slight_smile:

Moritz

[1] https://lists.osgeo.org/pipermail/grass-dev/2006-August/025250.html
[2] https://lists.osgeo.org/pipermail/grass-dev/2006-September/025858.html
[3] https://lists.osgeo.org/pipermail/grass-dev/2012-August/059178.html
[4] https://trac.osgeo.org/grass/ticket/2033

On Mon, Aug 8, 2016 at 5:27 AM, Blumentrath, Stefan <
Stefan.Blumentrath@nina.no> wrote:

In this context I am struggling with rendering speed in GRASS 7.0.4. I am
working on a relatively powerful server with local data in native GRASS
format.

There were improvements in 7.2, can you please test that and reply also to
#2234.

https://trac.osgeo.org/grass/ticket/2234