I am writing my first Python plugin. There was a problem during work. The plugin is designed to select a raster and calculate the statistics for the area bounded by the vector. I have created a list of rasters, but I do not know how to refer to the selected raster in the further part of the plugin to calculate statistics for it. The following code is created.

List of raster layers:

def create_layer_list(self):
    ''' Build list of layers'''
    self.layers = list(self.registry.mapLayers().values())
    #self.layers = self.iface.legendInterface().layers()
    layer_list = [""]+[layer.name() for layer in self.layers]

Main function for counting statistics:

def get_statistic(self):

      index2 = self.dialog.chooseCombo.currentIndex()
      rlayer = self.layers[index2].layer_list()
      provider = rlayer.dataProvider()

      for band in range(1, rlayer.bandCount() + 1):
        stats = provider.bandStatistics(band, QgsRasterBandStats.All, self.extent, 0)
        min = stats.minimumValue
        max = stats.maximumValue
        mean = stats.mean
        statsGathered = stats.statsGathered
        results= print ('min: {:.2f}, max: {:.2f}, mean: {:.2f}, statsGathered: {:.2f}'.format(min, max,mean,statsGathered)) 

Unfortunately, Python throws an error when indexing ..

1 Answer 1


Try referencing the selected layer by name:

def get_statistic(self):
    selected_layer = self.dialog.chooseCombo.currentText()
    rlayer = QgsProject.instance().mapLayersByName(selected_layer)[0]
    provider = rlayer.dataProvider()
  • 1
    I changed QgsMapLayerRegistry to QgsProject and it worked! Thank You!
    – iza4400
    Oct 15, 2019 at 19:55
  • @iza4400 - Apologies, you are indeed correct :)
    – Joseph
    Oct 16, 2019 at 9:01

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