Using with edit(layer): the changes will be committed automaticallyĬalling commitChanges() at the end. Here is how you can use the undo functionality:ĭirectly save changes using with based command Have the changes stored immediately, then you will have easier work by (If you do not care about undo/redo and want to In order to make undo/redo work properly, the above mentioned calls have to be addAttribute ( QgsField ( "mytext", QVariant. changeAttributeValue ( fid, fieldIndex, value ) 19 20 # add new field 21 layer.
#Deltacad delete within layers update#
changeGeometry ( fid, geometry ) 15 # update an attribute with given field index (int) to a given value 16 fieldIndex = 1 17 value = 'My new name' 18 layer. deleteFeature ( fid ) 11 12 # set new geometry (QgsGeometry instance) for a feature 13 geometry = QgsGeometry. addFeatures () 9 # delete a feature with specified ID 10 layer. setId ( fid ) 6 7 # add two features (QgsFeature instances) 8 layer.
#Deltacad delete within layers how to#
Here you have some examples that demonstrate how to use these editing methods.ġ from import QVariant 2 3 feat1 = feat2 = QgsFeature ( layer. To find out whether a layer is in editing mode, use the isEditable() method. One will discard them and will not modify the data source at all. The first one will commit all your changes to the data source, while the second The methods are similar to the ones we have seen in the provider, but they areįor these methods to work, the layer must be in editing mode. When changes are committed, all changes from the editing buffer are Will allow user to decide whether to commit/rollback and allows the usage of This option when providing some GUI tools for vector layer editing, since this Vector layer editing that complements the direct usage of data providers. This functionality also programmatically - it is just another method for Them - they stay in layer’s in-memory editing buffer. All the changes you make are not written until you commit Mode for a particular layer, then do some modifications and finally commit (or When editing vectors within QGIS application, you have to first start editing Modifying Vector Layers with an Editing Buffer Methods to edit geometries (translate, insert or move vertex, etc.). The QgsVectorLayerEditUtils which provides some useful If you only need to change geometries, you might consider using It contains all the attribute values of this feature 39 print ( attrs ) 40 # for this test only print the first feature 41 breakįavor QgsVectorLayerEditUtils class for geometry-only edits area ()) 34 else : 35 print ( "Unknown or invalid geometry" ) 36 # fetch attributes 37 attrs = feature. asMultiPolygon () 33 print ( "MultiPolygon: ", x, "Area: ", geom. asPolygon () 30 print ( "Polygon: ", x, "Area: ", geom. PolygonGeometry : 28 if geomSingleType : 29 x = geom. asMultiPolyline () 26 print ( "MultiLine: ", x, "length: ", geom. asPolyline () 23 print ( "Line: ", x, "length: ", geom. LineGeometry : 21 if geomSingleType : 22 x = geom. asMultiPoint () 19 print ( "MultiPoint: ", x ) 20 elif geom. asPoint () 16 print ( "Point: ", x ) 17 else : 18 x = geom. PointGeometry : 13 # the geometry type can be of single or multi type 14 if geomSingleType : 15 x = geom. geometry () 11 geomSingleType = QgsWkbTypes. id ()) 8 # fetch geometry 9 # show some information about the feature geometry 10 geom = feature. getFeatures () 4 5 for feature in features : 6 # retrieve every feature with its geometry and attributes 7 print ( "Feature ID: ", feature. You can retrieve information about the fields associated with a vector layerīy calling fields() on a QgsVectorLayer object:ġ # "layer" is a QgsVectorLayer instance 2 layer = iface. Retrieving information about attributes Most work here is based on the methods of the QgsVectorLayer class.
This section summarizes various actions that can be done with vector layers. Modifying Vector Layers with an Editing Buffer Tasks - doing heavy work in the background Expressions, Filtering and Calculating Values
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