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SF Migration Guide

HarryZhu edited this page Mar 18, 2020 · 13 revisions

Construction

definition sf geospark
Return a specified ST_Geometry value from Well-Known Text representation (WKT) st_as_sf(df,wkt="geom") ST_GeomFromText
Returns a specified ST_Geometry value from dataframe st_as_sf(df, coords = c("x", "y")) -
Construct a Geometry from WKB object st_read ST_GeomFromWKB
Construct a Geometry from Geojson object st_read ST_GeomFromGeojson
Return Well-Known Text representation (WKT) from a specified ST_Geometry value st_as_text ST_As_Text
Returns an ST_Point with the given coordinate values. OGC alias for ST_MakePoint st_point ST_Point
Returns a polygon built from the specified linestring and SRID st_polygon -
Coordinate Reference System / Spatial Reference System Transformation: for exmaple, from WGS84 (EPSG:4326, degree-based), to EPSG:3857 (meter-based) st_transform ST_Transform

Geometry Measurement

definition sf geospark
Return polygon area of a geometry st_area ST_Area
Return line length of a geometry st_length ST_Length
Return distance between two geomerties st_distance ST_Distance

DE9IM

definition sf geospark
spatial join st_join st_join
Returns TRUE if neither the two features’ boundaries intersect, nor the two elements intersect inside st_disjoint ST_Disjoint
Returns TRUE if the only points in common between A and B lie in the union of the boundaries of A and B st_touches ST_Touches
Returns TRUE if the given two geometry objects are "spatially cross" st_crosses ST_Crosses
Returns TRUE if the given Geometries are "spatially equal" st_equals ST_Equals
Returns TRUE if geometry B is completely inside geometry A st_contains ST_Contains
Returns TRUE if geometry A is completely inside geometry B st_within ST_Within
Returns TRUE if the Geometries "spatially overlap" st_overlaps ST_Overlaps
Overlaps, Touches, Within all imply spatial intersection st_intersects ST_Intersects

Aggregate function

definition sf geospark
Return the entire envelope boundary of all geometries in A - ST_Envelope_Aggr
Return the polygon union of all polygons in A st_union ST_Union_Aggr

More Advanced Operations

definition sf geospark
Return the Convex Hull of polgyon A st_convex_hull ST_ConvexHull
Return the envelop boundary of A st_envelope ST_Envelope
Return the centroid point of A st_centroid ST_Centroid
Reduce the decimals places in the coordinates of the geometry to the given number of decimal places. The last decimal place will be rounded st_set_precision ST_PrecisionReduce
Return TRUE if geometry's only self-intersections are at boundary points st_is_simple ST_IsSimple
Return TRUE if a geometry is well formed st_is_valid ST_IsValid
Returns a geometry/geography that represents all points whose distance from this Geometry/geography is less than or equal to distance st_buffer ST_Buffer

References