Bug report #11441

Parallel multi-core rendering glitches with OTF reprojection

Added by Anita Graser over 2 years ago. Updated about 1 month ago.

Status:Open Start Date:10/19/2014
Priority:Normal Due date:
Assigned to:- % Done:

0%

Category:Map Canvas
Target version:Version 3.0
Platform: Pull Request or Patch supplied:No
Platform version: Affected version:master
Status info: Causes crash or corruption:No
Resolution: Tag:

Description

With active on-the-fly reprojection and parallel rendering, the map renders with big artifacts. I've tested the following project with both the 2.4 release and today's nightly:

https://github.com/FOSS4GAcademy/GST101FOSS4GLabs/tree/master/Module%204%20Lab/QGIS%202.2/Lab%204%20Data

Deactivating either OTF or parallel rendering fixes the problem as far as I can tell.

glitch.png (235.8 kB) Anita Graser, 10/19/2014 03:23 am

projissues.PNG (223.2 kB) Anita Graser, 01/23/2016 10:32 am

glitch219.PNG (211.1 kB) Anita Graser, 01/09/2017 11:12 am


Related issues

related to QGIS Application - Bug report #11746: Vertical lines appear as artifacts when map has lots of l... Closed 11/26/2014

History

Updated by Giovanni Manghi over 2 years ago

  • Status changed from Open to Feedback

cannot confirm here, tested on master on both Linux and Windows (same project and data).

Updated by Gary Sherman over 2 years ago

Try turning off simplification and/or "Make lines appear less jagged..." and see if it goes away. We had a similar problem years ago and I don't recall the root cause.

Updated by Saber Razmjooei over 2 years ago

There are layers from outside the OTF CRS. According to this website: http://prj2epsg.org/epsg/5070 Canada and Mexico are outside EPSG:5070's CRS zone. I guess this causes the problem.

I have removed Mexico and Canada and the problem seems to have disappeared.

Updated by Anita Graser over 2 years ago

@Gary: Changing the simplification settings (values, on/off) or deactivating anti-aliasing didn't change the results.

@Saber: Even if I only use the US states (which should be within the CRS zone), these artifacts appear.

Updated by Saber Razmjooei over 2 years ago

It has become less frequent. To completely get rid of the problem, I saved western_states in 5070 and used that instead. But that does not explain the source of problem.

Updated by Martin Dobias over 2 years ago

I cannot replicate the problem.

@Anita / @Saber - which version of Proj.4 do you use? Does it happen also if you use a wgs84 for destination CRS? To my (brief) knowledge, the used epsg 5070 uses a grid file. Could you try some other projection for north america that does not involve reading of grid files? (based on parameters only)

Apparently the proj library versions < 4.8 were prone to errors when used in multi-threaded environment, but maybe we should also make use of contexts introduced in 4.8:
https://trac.osgeo.org/proj/wiki/ThreadSafety

Updated by Giovanni Manghi over 2 years ago

Martin Dobias wrote:

I cannot replicate the problem.

@Anita / @Saber - which version of Proj.4 do you use? Does it happen also if you use a wgs84 for destination CRS? To my (brief) knowledge, the used epsg 5070 uses a grid file. Could you try some other projection for north america that does not involve reading of grid files? (based on parameters only)

Apparently the proj library versions < 4.8 were prone to errors when used in multi-threaded environment, but maybe we should also make use of contexts introduced in 4.8: https://trac.osgeo.org/proj/wiki/ThreadSafety

it seems anyway strange to me as I tested also on Windows (where anyone should have the same libraries) and cannot replicate the issue.

Updated by Martin Dobias over 2 years ago

Giovanni Manghi wrote:

it seems anyway strange to me as I tested also on Windows (where anyone should have the same libraries) and cannot replicate the issue.

Unfortunately this is not that strange. It is quite common that errors in multi-threaded code appear just for some people, while working flawlessly for others.

Updated by Saber Razmjooei over 2 years ago

It works fine in both WGS84 and 4269.

Updated by Giovanni Manghi over 2 years ago

still true?

Updated by Anita Graser over 2 years ago

Still true for me (Win8 OSGeo4W nightly 64bit).

Updated by Giovanni Manghi almost 2 years ago

  • Status changed from Feedback to Open

Updated by Anita Graser almost 2 years ago

Still true for 2.8.1 (Win8 OSGeo4W 64bit).

Updated by Anita Graser over 1 year ago

  • Target version set to Future Release - High Priority

Still true for 2.11 today.

Updated by Martin Dobias over 1 year ago

  • Status changed from Open to Feedback

As far as I can tell from my tests, this problem was caused by a bug in proj.4 library: https://github.com/OSGeo/proj.4/issues/226

It has been fixed in proj 4.9.2 (released Sep 2015) which is now also available in osgeo4w (since end of Nov 2015). Could you please test again with the latest proj4 version to see if the problem is gone?

Updated by Anita Graser over 1 year ago

Unfortunately still around ... even with the new proj ..

Please put back to "open".

Updated by Anita Graser about 1 year ago

@Martin Can you please change the status back to open? Thanks!

Updated by Martin Dobias about 1 year ago

  • Status changed from Feedback to Open

Maybe we can have a look at it in Girona...

Updated by Giovanni Manghi 4 months ago

  • Status changed from Open to Feedback

is there any update on this issue?

Updated by Anita Graser 4 months ago

Still same error unfortunately. Tested with latest 2.19 in OSGeo4W - so not latest master

Updated by Jürgen Fischer 4 months ago

Anita Graser wrote:

so not latest master

not even master - qgis-dev is from (removed) master_2. qgis-rel-dev should be more up to date (branched off from master_2 on release of 2.18)

Updated by Giovanni Manghi 4 months ago

  • Status changed from Feedback to Open

Jürgen Fischer wrote:

Anita Graser wrote:

so not latest master

not even master - qgis-dev is from (removed) master_2. qgis-rel-dev should be more up to date (branched off from master_2 on release of 2.18)

There will ever be a master/qgis3 package on osgeo4w? Just a practical question: I do/did most of master testing on Windows because it was very practical, if there will be no more master on osgeo4w I will have to review my strategy and compile daily on Linux.

Updated by Jürgen Fischer 4 months ago

Giovanni Manghi wrote:

There will ever be a master/qgis3 package on osgeo4w?

sure.

Updated by Anita Graser 4 months ago

Jürgen Fischer wrote:

qgis-rel-dev should be more up to date (branched off from master_2 on release of 2.18)

Ok, I'll try with qgis-rel-dev

Updated by Anita Graser 4 months ago

Same issue in qgis-rel-dev

Updated by Giovanni Manghi about 1 month ago

  • Status changed from Open to Feedback
  • Priority changed from High to Normal
  • Target version deleted (Future Release - High Priority)
  • Affected version changed from master to 2.18.4

Anita Graser wrote:

Same issue in qgis-rel-dev

what about the (qgis3) master? any change?

Updated by Anita Graser about 1 month ago

Still same here with 2.99 from OSGeo4W.

Updated by Giovanni Manghi about 1 month ago

  • Status changed from Feedback to Open
  • Target version set to Version 3.0
  • Affected version changed from 2.18.4 to master

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