QGIS Geometry Copy – How to Copy Geometry Without Attributes Between Features

copygeometryqgis

With QGIS it's easy to add a new part to an existing feature/geometry but I can't see how to copy/paste this part from another existing feature/geometry.

Is it possible?

Best Answer

Yes it is possible, see instructions below:

Start an edit session on both layers that you want to do the copy/paste between.
Use the Select feature by rectangle tool to select the feature in the map (copy from).
Click the Edit (menu)>Copy Features button.
Highlight the layer in the TOC that the feature will be pasted to.
Click the Edit (menu)>Paste Features button.

Related Solutions

QGIS Layer Transfer – How to Copy Paste Layers Between Projects

just right click the layer and select save as...layer definition file and save... then from another project, click the layer menu and select add from layer definition file... and that's it. ;-)

QGIS Geometry – How to Copy Geometry from One Layer to Attributes of Another

I propose two different ways.

Using processing tools: see my answer to another question. It is not difficult to adapt it to your problem, since it is about polygon overlays
A Python script to copy&paste into Python console or to run from Python editor

The script get 2 layers A, B. Replace them with the names of your layers. B is the one providing the additional attributes. The resulting features go to a new memory layer with all attributes from both layers. Then it loops over all features from A searching for features from B, that contain the centroid of the A features. If such a B is found, take the geometry from A, and attributes from A and B , and write it to memory layer AB.

# get layers
a_layer = QgsMapLayerRegistry.instance().mapLayersByName('A')[0]
b_layer = QgsMapLayerRegistry.instance().mapLayersByName('B')[0]

# prepare result layer
ab_layer = QgsVectorLayer('Polygon?crs=epsg:4326', 'AB', 'memory')
ab_fields = a_layer.dataProvider().fields()
ab_fields.extend( b_layer.dataProvider().fields())
ab_prov = ab_layer.dataProvider()
ab_layer.startEditing()
ab_prov.addAttributes(ab_fields)
ab_layer.commitChanges()

ab_feats = []
# replace with a_layer.selectedFeatures() if you want seleted features only
for feat in a_layer.getFeatures():
    # to increase performance filter possible candidates 
    beefs = b_layer.getFeatures(QgsFeatureRequest().setFilterRect(feat.geometry().boundingBox()))
    for beef in beefs:
        # check if centroid of A is in B
        if feat.geometry().centroid().within(beef.geometry()):
            ab_feat = QgsFeature(ab_fields)
            ab_attrib = feat.attributes()
            ab_attrib.extend(beef.attributes())
            ab_feat.setAttributes(ab_attrib)
            ab_feat.setGeometry(beef.geometry())
            ab_feats.append(ab_feat)
            break

# add features to layer
ab_prov.addFeatures(ab_feats)
QgsMapLayerRegistry.instance().addMapLayers([ab_layer])

The script could be used as a template for other topological related feature comparisons as well.

Best Answer

Related Solutions

QGIS Layer Transfer – How to Copy Paste Layers Between Projects

QGIS Geometry – How to Copy Geometry from One Layer to Attributes of Another

Related Question