PyQGIS – Display Only Visible Canvas Features in Attribute Table

attribute-tablefiltermapcanvaspyqgisselect-by-expression

As explained by @xunilk in Getting attribute values from vector features visible in QGIS canvas using PyQGIS we can easily access to the attribute values of the features visible in the QGIS canvas (code below)

layer = iface.activeLayer()
mapcanvas = iface.mapCanvas()
rect = mapcanvas.extent()

request = QgsFeatureRequest().setFilterRect(rect)

selected_feats = layer.getFeatures(request)

attr = [ feat.attributes() for feat in selected_feats ]

print(attr)

However I'm struggling to find a way to display, in the attribute table, only the values of the visible features.

Do you have any suggestions?

Best Answer

I dont know what can be done in plugins and not, but in QGIS you can apply a filter:

layer = iface.activeLayer()
mapcanvas = iface.mapCanvas()
rect = mapcanvas.extent()
request = QgsFeatureRequest().setFilterRect(rect)
selected_feats = layer.getFeatures(request)

ids = [f.id() for f in selected_feats]
where_clause = '"id" IN{0}'.format(tuple(ids))
layer.setSubsetString(where_clause)

Related Solutions

pyqgis – How to Get Attribute Values from Vector Features Visible in QGIS Canvas

Yes, it is possible by using a QgsFeatureRequest with 'setFilterRect' method. The argument of this method is a QgsRectangle object obtained for visible part of Map Canvas with its 'extent' method (QgsMapCanvas class). I tried out my approach with this code:

layer = iface.activeLayer()
mapcanvas = iface.mapCanvas()
rect = mapcanvas.extent()

request = QgsFeatureRequest().setFilterRect(rect)

selected_feats = layer.getFeatures(request)

attr = [ feat.attributes() for feat in selected_feats ]

print attr

print len(attr)

and world_borders shapefile that has 3784 features. After running the code with the next image situation:

I got the display of only 77 visible features attributes (printed result at the Python Console of GIS).

PyQGIS – Adding and Filtering Layer with Map Canvas Extent

You can create a temporary layer based on your Postgis layer.

You can either filter features of the layer wich intersect the canvas extent, or filter the features wich are completly within the canvas extent.

On the example below, I have a layer (red), a canvas extent (red line) zoomed on the green feature, features intersecting the extent (pink features) and features within the extent (purple features).

To create those 2 layers I used this code :

import tempfile
tf = tempfile.TemporaryDirectory()

# IMPORT YOUR LAYER

if self.ctrs_cibles.featureCount() > 0:
    # Creation of the layer with the features wich intersect the extent
    self.ctrs_cibles.selectByRect(extent)
    writer = QgsVectorFileWriter.writeAsVectorFormat(self.ctrs_cibles, tf.name +'/'+'filtered_layer_intersect.shp', "utf-8", self.ctrs_cibles.crs(), "ESRI Shapefile", onlySelected=True)
    iface.addVectorLayer( tf.name +'/'+'filtered_layer_intersect.shp', '', 'ogr')
    # Creation of the layer with the features wich are within the extent
    inside_extent_ids = []
    for feature in self.ctrs_cibles.getSelectedFeatures():
        if feature.geometry().within(QgsGeometry().fromRect(extent)):
            inside_extent_ids.append(feature.id())
    self.ctrs_cibles.selectByIds(inside_extent_ids)
    writer = QgsVectorFileWriter.writeAsVectorFormat(self.ctrs_cibles, tf.name +'/'+'filtered_layer_within.shp', "utf-8", self.ctrs_cibles.crs(), "ESRI Shapefile", onlySelected=True)
    iface.addVectorLayer( tf.name +'/'+'filtered_layer_within.shp', '', 'ogr')

Best Answer

Related Solutions

pyqgis – How to Get Attribute Values from Vector Features Visible in QGIS Canvas

PyQGIS – Adding and Filtering Layer with Map Canvas Extent

Related Question