Extracting and saving polygons by attribute in QGIS [duplicate]

Question

I have a shapefile layer from a vegetation mapping project with 417 polygons that represent 21 different vegetation classes. These are stored in a single column called "type".

I want to break the .shp file down into each different vegetation class, so that I end up with 21 .shp layers, one for each class.

How can I do this efficiently in QGIS?

I have added a screenshot of the shapefile (from MapInfo, but I want to use QGIS for the disaggregation).

Answer 1

Use the "Split Vector Layer" processing tool called via Vector > Data Management Tools > Split Vector Layer....

In the dialog that opens, just choose the column with your attribute for the unique "ID".

Answer 2

I know you said no Python, but this is an easy code you can use in the Python console in QGIS, I will make the comments shown by # where you have to change some names according to your project.

• Change Your_shapefile for the name of your shapefile
• Change: ATTRIBUTE = the column name where you want to extract the polygon. Change: VALUE = the value you want to extract
• Change the path C:\Users\Extracted_values where you want to store the new shapefile, and keep the ending .shp

layers = QgsProject.instance().mapLayersByName("Your_shapefile")  # Change Your_shapefile for the name of your shapefile
if len(layers) > 0:
    layer = layers[0]
    layer.selectByExpression('"ATTRIBUTE" = VALUE') # Change : ATTRIBUTE = 
  the column name where you want to extract the polygon.  Change: VALUE = the value you want to extract 
    fn = r"C:\Users\Extracted_values.shp" # Change the path where you want to store the new shapefile
    writer = QgsVectorFileWriter.writeAsVectorFormat(layer, fn, 'utf-8', driverName='ESRI Shapefile', onlySelected=True)
    del writer
    Selected_layer = iface.addVectorLayer(fn, '', 'ogr')
else:
    print("Layer 'Your_shapefile' not found in the project.") #