[QGIS-trac] Re: [Quantum GIS] #1219: OTFT on, layer's and project's CRS the same: measure tools and Identify Features return impossible measurments

[Quantum GIS]

#1219: OTFT on, layer's and project's CRS the same: measure tools and Identify
Features return impossible measurments
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        Reporter:  smizuno                          |         Owner:  homann           
            Type:  bug                              |        Status:  assigned         
        Priority:  minor: annoyance or enhancement  |     Milestone:  Version 1.0.1    
       Component:  Projection Support               |       Version:  HEAD             
      Resolution:                                   |      Keywords:  measure area line
Platform_version:                                   |      Platform:  All              
        Must_fix:  Yes                              |   Status_info:  0                
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Changes (by homann):

  * priority:  critical: causes crash or data corruption => minor:
               annoyance or enhancement
  * status:  new => assigned
  * owner:  nobody => homann
  * milestone:  Version 1.0.0 => Version 1.0.1

Comment:

 The UI is confusing, no doubt about it.

 When OTF proj is off, we don't use the CRS at all. All layer poits are
 unitless. So there is no way of telling if your square (0,0) - (10,10) is
 100 square meter, 100 square feet or 100 square parsec. That's why the
 unit selection exists in the first place.

 When OTF is on, we figure out the unit from the canvas projection. If a
 geocs such as WGS84, the unit is set to degrees, else if it is UTM it is
 set to meter.

 An idea is to grey out the unit selection possibility when OTF proj is on,
 might make it less confusing.

 It is not ideal, but we should figure out how to do it once and for all
 and write it down. The I can fix it. I'll leave this as an ehancement

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Ticket URL: <https://trac.osgeo.org/qgis/ticket/1219#comment:7>
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