[Qgis-user] Change Projection in Projection Properties from a Python PlugIn

[bjsvwpfe]

Hi,

a couple of weeks ago I had problems with changing Projection Properties
from a PlugIn.
With the solution from Martin everything worked fine in the PlugIn.
Now I've put the code from the run section in the __init__ section of
another PlugIn which every user needs because we don't want that our users
have to click a button for having these project settings.
The project settings are set automatically now.
But theres a little problem which I don't understand.

If you want to load a WMS-Layer the necessary projection isn't set. It's
still WGS84. Everything else is working fine.
If I put the code in the run section the projection of the WMS-Layer is set
automatically to the projection we need.

Here is the code:

def __init__(self, iface):
    # Save reference to the QGIS interface
    self.iface = iface
    srs = QgsSpatialRefSys()
    srs.createFromEpsg(21781)
    self.canvas = self.iface.getMapCanvas()
    self.canvas.setMapUnits(QGis.METERS)
    self.rect = self.canvas.extent()
    mapRender = self.canvas.mapRender()
    mapRender.setDestinationSrs(srs)
    mapRender.setProjectionsEnabled(1)
    mapRender.fullExtent()
    self.canvas.refresh()
   
QgsProject.instance().writeEntry("SpatialRefSys","/ProjectSRSProj4String",srs.proj4String())

Any explains for this behaviour?

thx for your answers.

Michael

bjsvwpfe wrote:
> 
> On Thu, May 29, 2008 at 12:24 PM, bjsvwpfe <Michael.Pfeiffer at bd.so.ch>
> wrote:
>>>
>>> Hi,
>>>
>>> thanks for the answers. That was exactly what I'm searching for
>>> :jumping:
>>> So its possible for me to set the project settings now.
>>> But theres still a last little problem. I make the settings with the
>>> following code:
>>>
>>>    srs = QgsSpatialRefSys()
>>>    srs.createFromEpsg(21781)
>>>    self.canvas = self.iface.getMapCanvas()
>>>    self.canvas.setMapUnits(QGis.METERS)
>>>    self.rect = self.canvas.extent()
>>>    mapRender = self.canvas.mapRender()
>>>    mapRender.setDestinationSrs(srs)
>>>    mapRender.setProjectionsEnabled(1)
>>>    self.canvas.refresh()
>>>
>>> But the project settings are not applied to the map. You still have to
>>> press
>>> the apply Button in the Project Settings.
>>> How can I solve this last problem so that it is not necessary to press
>>> the
>>> apply button.
> 
>>This should set the destination SRS to project settings:
>>QgsProject.instance().writeEntry("SpatialRefSys","/ProjectSRSProj4String",
>>proj4string)
>>where proj4string is proj4 definition of the SRS and can be obtained
>>from QgsSpatialRefSys
>>
>>Hope that helps
>>Martin
>>_______________________________________________
>>Qgis-user mailing list
>>Qgis-user at lists.osgeo.org
>>http://lists.osgeo.org/mailman/listinfo/qgis-user
>>
> 
> Yes thats it. Thank you very much Martin :handshake:
> 
> Greets
> 
> Michael
> 

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