Aliases: st_collection_extract st_collection_extract.sfg st_collection_extract.sfc st_collection_extract.sf
Keywords:
### ** Examples pt <- st_point(c(1, 0)) ls <- st_linestring(matrix(c(4, 3, 0, 0), ncol = 2)) poly1 <- st_polygon(list(matrix(c(5.5, 7, 7, 6, 5.5, 0, 0, -0.5, -0.5, 0), ncol = 2))) poly2 <- st_polygon(list(matrix(c(6.6, 8, 8, 7, 6.6, 1, 1, 1.5, 1.5, 1), ncol = 2))) multipoly <- st_multipolygon(list(poly1, poly2)) i <- st_geometrycollection(list(pt, ls, poly1, poly2)) j <- st_geometrycollection(list(pt, ls, poly1, poly2, multipoly)) st_collection_extract(i, "POLYGON")
Geometry set for 2 features Geometry type: POLYGON Dimension: XY Bounding box: xmin: 5.5 ymin: -0.5 xmax: 8 ymax: 1.5 CRS: NA
st_collection_extract(i, "POINT")
st_collection_extract(i, "LINESTRING")
## A GEOMETRYCOLLECTION aa <- rbind(st_sf(a=1, geom = st_sfc(i)), st_sf(a=2, geom = st_sfc(j))) ## With sf objects st_collection_extract(aa, "POLYGON")
Simple feature collection with 5 features and 1 field
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: 5.5 ymin: -0.5 xmax: 8 ymax: 1.5
CRS: NA
a geom
1.2 1 MULTIPOLYGON (((5.5 0, 7 0,...
1.3 1 MULTIPOLYGON (((6.6 1, 8 1,...
2.2 2 MULTIPOLYGON (((5.5 0, 7 0,...
2.3 2 MULTIPOLYGON (((6.6 1, 8 1,...
2.4 2 MULTIPOLYGON (((5.5 0, 7 0,...
st_collection_extract(aa, "LINESTRING")
Simple feature collection with 2 features and 1 field
Geometry type: LINESTRING
Dimension: XY
Bounding box: xmin: 3 ymin: 0 xmax: 4 ymax: 0
CRS: NA
a geom
1.1 1 LINESTRING (4 0, 3 0)
2.1 2 LINESTRING (4 0, 3 0)
st_collection_extract(aa, "POINT")
Simple feature collection with 2 features and 1 field Geometry type: POINT Dimension: XY Bounding box: xmin: 1 ymin: 0 xmax: 1 ymax: 0 CRS: NA a geom 1 1 POINT (1 0) 2 2 POINT (1 0)
## With sfc objects st_collection_extract(st_geometry(aa), "POLYGON")
Geometry set for 5 features Geometry type: MULTIPOLYGON Dimension: XY Bounding box: xmin: 5.5 ymin: -0.5 xmax: 8 ymax: 1.5 CRS: NA
st_collection_extract(st_geometry(aa), "LINESTRING")
Geometry set for 2 features Geometry type: LINESTRING Dimension: XY Bounding box: xmin: 3 ymin: 0 xmax: 4 ymax: 0 CRS: NA
st_collection_extract(st_geometry(aa), "POINT")
Geometry set for 2 features Geometry type: POINT Dimension: XY Bounding box: xmin: 1 ymin: 0 xmax: 1 ymax: 0 CRS: NA
## A GEOMETRY of single types bb <- rbind( st_sf(a = 1, geom = st_sfc(pt)), st_sf(a = 2, geom = st_sfc(ls)), st_sf(a = 3, geom = st_sfc(poly1)), st_sf(a = 4, geom = st_sfc(multipoly)) ) st_collection_extract(bb, "POLYGON")
Simple feature collection with 2 features and 1 field Geometry type: MULTIPOLYGON Dimension: XY Bounding box: xmin: 5.5 ymin: -0.5 xmax: 8 ymax: 1.5 CRS: NA a geom 3 3 MULTIPOLYGON (((5.5 0, 7 0,... 4 4 MULTIPOLYGON (((5.5 0, 7 0,...
## A GEOMETRY of mixed single types and GEOMETRYCOLLECTIONS cc <- rbind(aa, bb) st_collection_extract(cc, "POLYGON")
Simple feature collection with 7 features and 1 field
Geometry type: MULTIPOLYGON
Dimension: XY
Bounding box: xmin: 5.5 ymin: -0.5 xmax: 8 ymax: 1.5
CRS: NA
a geom
1.2 1 MULTIPOLYGON (((5.5 0, 7 0,...
1.3 1 MULTIPOLYGON (((6.6 1, 8 1,...
2.2 2 MULTIPOLYGON (((5.5 0, 7 0,...
2.3 2 MULTIPOLYGON (((6.6 1, 8 1,...
2.4 2 MULTIPOLYGON (((5.5 0, 7 0,...
5 3 MULTIPOLYGON (((5.5 0, 7 0,...
6 4 MULTIPOLYGON (((5.5 0, 7 0,...