Bug 279431

Summary:	Check tiles before writing to disk
Product:	[Applications] marble	Reporter:	Dennis Nienhüser <nienhueser>
Component:	general	Assignee:	marble-bugs
Status:	CONFIRMED ---
Severity:	normal	CC:	rhardy702
Priority:	NOR
Version:	unspecified
Target Milestone:	some future version
Platform:	Compiled Sources
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Dennis Nienhüser 2011-08-05 09:28:33 UTC

Version:           unspecified (using KDE 4.7.0) 
OS:                Linux

When using WLAN connections or similar that return login pages, a request for a tiles from some server do not return the image data, but that login page. This results in invalid tiles stored on disk, which is even worse if a valid tile existed before. Therefore tiles should be checked for validity before writing them to disk.


Reproducible: Didn't try

Steps to Reproduce:
Didn't see the problem myself, but reported here: http://talk.maemo.org/showpost.php?p=1064231&postcount=164


Expected Results:  
Stupid bug wizard wants an entry here.

Comment 1 Tom Hardy 2013-07-27 04:38:11 UTC

This appears to be the bug affecting me the most at the moment--an ever increasing number of corrupted or misplaced tiles under Marble 1.5, KDE 4.10.5, until I do some cleanup, and then It starts again.

My use case is a Linux laptop mounted in a car,  logging into a large number of WiFi hotspots, very likely for a few seconds at a time as I drive by.

Corrupted tiles are evidenced by Marble using a fuzzy tile from another zoom level.  When I have bothered to dig one out, it was indeed labeled as corrupted by an image viewer.  I never thought to see if it was a web page of something.

Misplaced tiles show fine, but are displaced from an adjacent position or more than a  kilometer away.  They can be from a different zoom level.  I won't try to explain but I move a lot, and perhaps change zoom levels for one reason or another.

It would be an improvement if automatic downloading could be disabled.

Alternatively, couldn't you use use something like wget or libcurl for file downloading?  I would think you shouldn't need to completely reinvent the wheel.

Comment 2 Dennis Nienhüser 2013-07-27 06:53:43 UTC

While it does not solve the original problem, a quick workaround is setting Marble to offline mode (File => Work offline). It does not attempt to download/update tiles in offline mode.

You can delete broken tiles from the cache like this (one line):
find ~/.local/share/marble/maps/earth/openstreetmap -type f -name "*.png" \( -exec identify {} \; -o -delete \)

identify is part of imagemagick.

Comment 3 Tom Hardy 2013-07-28 01:40:59 UTC

Thanks!

Regarding "Work Offline", why didn't I think of that?

Comment 4 Justin Zobel 2021-03-09 22:51:44 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.