[QGIS-trac] Re: [Quantum GIS] #1219: Measure tools and Identify (derived area, line) report incorrect values when On-The-Fly projection is enabled

[Quantum GIS]

#1219: Measure  tools and Identify (derived area, line) report incorrect values
when On-The-Fly projection is enabled
--------------------------------------------------------------+-------------
        Reporter:  smizuno                                    |         Owner:  nobody           
            Type:  bug                                        |        Status:  new              
        Priority:  critical: causes crash or data corruption  |     Milestone:  Version 1.0.0    
       Component:  MapCanvas                                  |       Version:  HEAD             
      Resolution:                                             |      Keywords:  measure area line
Platform_version:                                             |      Platform:  All              
        Must_fix:  Yes                                        |   Status_info:  0                
--------------------------------------------------------------+-------------
Changes (by msieczka):

  * priority:  major: does not work as expected => critical: causes crash
               or data corruption
  * must_fix:  No => Yes

Comment:

 Ahh, now I understand what's the problem. Summary for Folks if anybody was
 missing the point like I did:

 1. Download the attached Shapefiles.

 2. Load them in QGIS. They are in EPSG:26915 - set you project's CRS the
 same *and enable "On The Fly transformation"*.

 3. You'll start getting weird, huge measurment results with OTFT enabled.
 Such as:

 {{{
 Area of the smaller square:

                     OTFT off    OTFT on

 Identify Features   1 m2        104600 m2 (sic!)
 Measure Area        1 m2        various weird values of 5 - 10 000 m2
 }}}

 Quite a bug.

-- 
Ticket URL: <http://trac.osgeo.org/qgis/ticket/1219#comment:4>
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