Usando solo due layer linea_a e linea_b e tematizzare usando il GENERATORE DI GEOMETRIE
Unione
UNION(
make_line( -- linea a
start_point(geometry(get_feature_by_id('linea_a',1))),
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1)))),
make_line( -- linea b
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1))),
end_point($geometry))
)
NB: per gli shapefile sostituire 0 al posto di 1; es: ('linea_a',0)
Differenza Smmetrica
SYM_DIFFERENCE(
make_line( -- linea a
start_point(geometry(get_feature_by_id('linea_a',1))),
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1)))),
make_line( -- linea b
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1))),
end_point($geometry))
)
Differnza
DIFFERENCE(
make_line( -- linea a
start_point(geometry(get_feature_by_id('linea_a',1))),
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1)))),
make_line( -- linea b
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1))),
end_point($geometry))
)
DIFFERENCE(
make_line( -- linea b
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1))),
end_point($geometry)),
make_line( -- linea a
start_point(geometry(get_feature_by_id('linea_a',1))),
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1))))
)
Intersezione
INTERSECTION(
make_line( -- linea a
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1))),
end_point($geometry)),
make_line( -- linea b
start_point(geometry(get_feature_by_id('linea_a',1))),
start_point($geometry),
end_point(geometry(get_feature_by_id('linea_a',1))))
)
pigrecoinfinito 
Dove posso trovare altro materiale per imparare ad usare il “linguaggio” di Qgis?
"Mi piace"Piace a 1 persona
Ciao Nicola,
se alludi alle espressioni, in questo link trovi una mia guida #HfcQGIS
—
http://hfcqgis.opendatasicilia.it/it/latest/
"Mi piace""Mi piace"
Stre-pi-to-so! 🙂
"Mi piace"Piace a 1 persona