[Qgis-developer] Not Rendering the Shapefile in Canvas - Blank

[Noli Sicad]

I solved it. I am using Ubuntu 10.04

I need to properly place the QGIS Install directory

qgis_prefix = os.getenv("/usr")


And I have to put, QgsApplication.setPrefixPath("/usr", True)

Instead of using: QgsApplication.setPrefixPath(qgis_prefix, True)

Here's the code.

def main(argv):
  # create Qt application
  app = QApplication(argv)

  # Initialize qgis libraries
  QgsApplication.setPrefixPath("/usr", True)
  QgsApplication.initQgis()

  # create main window
  wnd = ShapeViewer()
  # Move the app window to upper left
  wnd.move(100,100)
  wnd.show()

  # run!
  retval = app.exec_()

  # exit
  QgsApplication.exitQgis()
  sys.exit(retval)

if __name__ == "__main__":
  main(sys.argv)


Noli



On 9/10/10, Noli Sicad <nsicad at gmail.com> wrote:
> Hi  Cédric
>
> I inserted self.canvas.refresh() as showed below but still a blank canvas.
>
> ~~~~~~~~
>  # Set up the map canvas layer set
>     cl = QgsMapCanvasLayer(layer)
>     layers = [cl]
>     self.canvas.setLayerSet(layers)
>     self.canvas.refresh()
> ~~~~~~~~~
>
> Thanks.
>
> Noli
>
>
> On 9/10/10, Möri Cedric <Cedric.Moeri at bd.so.ch> wrote:
>> Hi Noli
>>
>> seems you're missing self.canvas.refresh() at the end of your code.
>>
>> regards
>> Cédric
>>
>> mit freundlichen Grüssen
>>
>> Cédric Möri
>> GIS-Informatiker
>>
>> --
>> Kanton Solothurn
>> Bau- und Justizdepartement
>> Amt für Geoinformation
>> Rötistrasse 4
>> 4501 Solothurn
>>
>> Telefon: +41 (0)32 627 24 75
>> Telefax: +41 (0)32 627 22 14
>> mailto:cedric.moeri at bd.so.ch
>> http://www.agi.so.ch
>>
>>
>> ----- Originalnachricht -----
>> Von: "Noli Sicad" <nsicad at gmail.com>
>> Gesendet: Fre, 10.9.2010 14:03
>> An: qgis-developer <qgis-developer at lists.osgeo.org>
>> Betreff: [Qgis-developer] Not Rendering the Shapefile in Canvas - Blank
>>
>> Hi,
>>
>> Is there any reason why the shapefile is not rendering in this code
>> (below)? I tried several shapefiles and yet I am getting a white
>> canvas or blank canvas without a render. I was able to open the
>> shapefile and the form with mapcanvas are showing. Yet no render of
>> the polygons - totally blank.
>>
>> self.canvas.setCanvasColor(Qt.white)  <---- a White Canvas without
>> render - BLANK
>>
>> Thanks. Noli
>>
>>
>> ~~~~~~~~~~~~~~~~
>> class ShapeViewer(QMainWindow, Ui_MainWindow):
>>
>>   def __init__(self):
>>     QMainWindow.__init__(self)
>>
>>     # Required by Qt4 to initialize the UI
>>     self.setupUi(self)
>>
>>     # Set the title for the app
>>     self.setWindowTitle("ShapeViewer")
>>
>>     # Create the map canvas
>>     self.canvas = QgsMapCanvas()
>>     self.canvas.useImageToRender(False)
>>     self.canvas.show()
>>
>>     # Lay our widgets out in the main window using a
>>     # vertical box layout
>>     self.layout = QVBoxLayout(self.frame)
>>     self.layout.addWidget(self.canvas)
>>
>>     # layout is set - open a layer
>>     # Add an OGR layer to the map
>>     file = QFileDialog.getOpenFileName(self,
>>                    "Open Shapefile", ".", "Shapefiles (*.shp)")
>>     fileInfo = QFileInfo(file)
>>
>>     # Add the layer
>>     layer = QgsVectorLayer(file, fileInfo.fileName(), "ogr")
>>
>>     if not layer.isValid():
>>       return
>>
>>      # Add layer to the registry
>>     QgsMapLayerRegistry.instance().addMapLayer(layer);
>>
>>     # Set extent to the extent of our layer
>>     self.canvas.setExtent(layer.extent())
>>
>>     # Set up the map canvas layer set
>>     cl = QgsMapCanvasLayer(layer)
>>     layers = [cl]
>>     self.canvas.setLayerSet(layers)
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