Bug 155572

Summary:	Performance degrades when zooming in at the north pole
Product:	[Applications] marble	Reporter:	Diederik van der Boor <vdboor>
Component:	general	Assignee:	marble-bugs
Status:	CONFIRMED ---
Severity:	normal	CC:	jtamate, marble-bugs, nienhueser, qilixue
Priority:	NOR
Version:	unspecified
Target Milestone:	---
Platform:	unspecified
OS:	Linux
Latest Commit:		Version Fixed In:

Description Diederik van der Boor 2008-01-12 21:31:21 UTC

Version:           0.5 -- KDE 4.0 Branch (using KDE 4.00.00 (KDE 4.0.0) "release 1.2", compiled sources)
Compiler:          gcc
OS:                Linux (i686) release 2.6.22.13-0.3-default

When zooming in at the north pole, the marble seems to hang for a short while. The performance is lower compared to zooming elsewhere.

Comment 1 Torsten Rahn 2008-01-12 23:30:54 UTC

Thanks for your bug report.

Actually this is a pretty funny bug report because it's a very well-known GIS-problem that can't get fixed using the current way we map the sphere.

Additionally when approaching one of the poles closely I suggest that you measure the memory Marble takes: you'll discover that it goes up dramatically.
Try the same with Google Earth and Nasa World Wind and you might experience similar issues because they use almost the very same concept of mapping the sphere!

The only way to fix this would be to use some different concepts, like e.g. the one called "quaternary triangular meshes (QTM)". However one of the drawbacks of triangular meshes is the fact that they are quite a bit harder to understand and calculate IMHO thereby increasing the barrier to take part in Marble development. 

Given that we don't expect people to look much at the north pole area this bug probably won't get addressed any time soon.

Comment 2 Torsten Rahn 2008-01-12 23:32:41 UTC

assigned.

Comment 3 Jaime Torres 2009-05-23 22:57:51 UTC

Can this bug considered fixed?
Apart from the fact that you could see (if enabled) 360 lines in 360 degrees, I do not notice a significant speed reduction compared to other places using KDE 4.2.87 (KDE 4.3 >= 20090519).

Comment 4 Torsten Rahn 2009-05-24 20:56:18 UTC

No, it's a conceptual bug that one might consider a "wontfix":

If you look directly at a pole the amount of tiles that have to be loaded immediately for each level will double. So at some point e.g. Marble has to load e.g. 1024 tiles from one moment to another.

Other virtual globes (like Google Earth, etc.) suffer from the same problem.

Comment 5 Justin Zobel 2021-03-09 22:51:43 UTC

Thank you for the bug report.

As this report hasn't seen any changes in 5 years or more, we ask if you can please confirm that the issue still persists.

If this bug is no longer persisting or relevant please change the status to resolved.