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)))) )
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