wrong scale displayed in map canvas

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Author Name: Regis Haubourg (@haubourg)
Original Redmine Issue: 4560

Assignee: Giuseppe Sucameli

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Hi ,
I upgraded Qgis 1.1 to 1.7.2 this morning. There is a major bug in map scale display in map canvas. It displays enormous numbers. I'm under Windows XP. I used standalone installer. project projection and data are epsg 2154 (France Lambert 93).
Side effect of this, all visibility levels are misinterpreted by qgis.

In my opinion, this is a critical bug, if confirmed, and requires an update of installers recently launched.

Régis

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• scale_bug.jpg (Regis Haubourg)
• lacs.zip (Regis Haubourg)

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Author Name: Regis Haubourg (@haubourg)

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I upgraded 1.7.1 to 1.7.2 not "1.1 to 1.7.2

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Author Name: Gary Sherman (@g-sherman)

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Filed under wrong project. Moved to QGIS

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• project_id was changed from 4 to 17
• assigned_to_id removed Gary Sherman

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Author Name: Regis Haubourg (@haubourg)

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Sorry for that Gary. Régis

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Author Name: Regis Haubourg (@haubourg)

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The bug seems related to projection behaviour.
When i switch project projection to IGN:LAMB93 (ID10089), scale is OK. When I go back to epsg 2154, wrong scale comes back.

EPSG:2154 is the old epsg definition for lambert 93. Datas I use are defined in EPSG:2154.
If i reproject on the fly to 4326 WGS84, scale stays wrong. If I switch to IGN:LAMB93, then switch to 4326, scale is OK..

régis

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Author Name: Richard Duivenvoorde (@rduivenvoorde)

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seems a small dataset, can you make it available to this issue?

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Author Name: Regis Haubourg (@haubourg)

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Here comes a dataset that reproduce the bug on my computer.
Régis

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• 3564 was configured as lacs.zip

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• lacs.zip (Regis Haubourg)

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Author Name: Richard Duivenvoorde (@rduivenvoorde)

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I've installed 1.7.2 on a fresh XP here

Loading your data in it, makes it a epsg:4326 project with your data loaded as epsg:2154 (which is ok). At that moment the scale shows huge numbers (as you show),

BUT after setting the project crs to epsg:2154 also AND setting the units to meters (were degrees with me, don't know why. epsg:2154 is a projected crs isn't it?), the scale seems ok to me?

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Author Name: Regis Haubourg (@haubourg)

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I think you found the bug. It seems that Qgis keep decimal degrees as units in memory, when on the fly reprojection activated. User interface is greyed out and meters are checked as units on screen.

Playing with those parameters (activating meters units / checking on the fly reprojection) generates Qgis crashes! Something strange lying under.

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Author Name: Richard Duivenvoorde (@rduivenvoorde)

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yes, confirmed here both on a machine running XP with osgeo4w (and upgrading from 1.7.0 to 1.7.2) and a machine running XP where I installed a fresh 1.7.2 via the standalone installer:

• as soon as you have some 'recently used coordinate reference systems', and you try to select one in the crs tab of the Project properties, go to the first tab and then back to the crs tab qgis just crashes. In the event viewer there is only a message about a crash in a qt-treewidget

• on the osgeo4w I also installed the dev/nightly version, and that one does NOT have the problem

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• fixed_version_id was configured as Version 1.7.2

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Author Name: Giuseppe Sucameli (@brushtyler)

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The problem was fixed in master by 62ed7ef.

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Author Name: Anita Graser (@anitagraser)

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I can confirm the crashes Richard described in 1.7.2 on Ubuntu.

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Author Name: Werner Macho (Werner Macho)

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applied patch 62ed7ef into release-1_7 to prepare for 1.7.3 release
gotta take a look if is is already fixed in upcoming 1.8
closing this for now as it works (for me) after applying the patch

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• status_id was changed from Open to Closed
• assigned_to_id was configured as Werner Macho
• resolution was changed from to fixed

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Author Name: Giuseppe Sucameli (@brushtyler)

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Anita Graser wrote:

I can confirm the crashes Richard described in 1.7.2 on Ubuntu.

And I fixed that crash in master by commit 98d5a76

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Author Name: Giuseppe Sucameli (@brushtyler)

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Werner Macho wrote:

applied patch 62ed7ef into release-1_7 to prepare for 1.7.3 release
gotta take a look if is is already fixed in upcoming 1.8
closing this for now as it works (for me) after applying the patch

You should backport also commit c0dc60b, both this and mine (98d5a76) fixed crashes in select projection dialog due to commit 2034d59 (a very dangerous change because it's into a showEvent method: a one-line change has required 2 other commit to work well again!).

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Author Name: Giuseppe Sucameli (@brushtyler)

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I hope that removing ticket resolution will re-open the ticket.

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• resolution was changed from fixed to

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Author Name: Giuseppe Sucameli (@brushtyler)

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No, no way to reopen the ticket... Ok, I'm going to open a new ticket for the crashes.

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• resolution was changed from to fixed

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Author Name: Werner Macho (Werner Macho)

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• resolution was changed from fixed to worksforme
• assigned_to_id was changed from Werner Macho to Giuseppe Sucameli

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Author Name: Giuseppe Sucameli (@brushtyler)

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Now this ticket is really fixed in release-1_7 branch, commit ids:
05e70ff
70e2dc3

Thanks macho for the backports!

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• resolution was changed from worksforme to fixed