2

I want to make a buffer on the start or end point of the line and not the line itself.

Is there some thing in QGIS python plugin development that can get me the points?

6

You can use v.to.points Processing Toolbox Algorithm.

At the next image, it can be observed:

  • Filtering by v.to.points
  • Selecting 'line' (shapefile used in this example) in 'Input lines layer'
  • Marking 'Write line nodes' option

enter image description here

After click in Run, I got "start and end points of each feature" in the shapefile line layer.

enter image description here

However, by using 'Write line vertices' option you can get all points:

enter image description here

11

You can use the following code to get the start and end points of your line layer and loads this as a memory point layer:

line_layer = qgis.utils.iface.activeLayer()
feat = QgsFeature()

point_layer = QgsVectorLayer("Point?crs=epsg:4326", "point_layer", "memory")
pr = point_layer.dataProvider()

for feature in line_layer.getFeatures():
    geom = feature.geometry().asPolyline()
    start_point = QgsPoint(geom[0])
    end_point = QgsPoint(geom[-1])
    feat.setGeometry(QgsGeometry.fromPoint(start_point))
    pr.addFeatures([feat])
    feat.setGeometry(QgsGeometry.fromPoint(end_point))
    pr.addFeatures([feat])

QgsMapLayerRegistry.instance().addMapLayer(point_layer)

Result:

Result

You can then use this memory layer to create buffers around the points.

  • how to extend this and add attribute coluns from line object? – Paulo Cardoso Feb 8 '18 at 14:34
  • 1
    @PauloCardoso - Probably something like feat.setAttributes(feature.attributes())? You should ask this as a new question :) – Joseph Feb 8 '18 at 14:40
6
layer # your vector layer (line type)

for feature in layer.getFeatures():
    geom = feature.geometry().asPolyline()
    print "Start: " + geom[0]
    print "End: " + geom[-1]

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