Intersect

Draft: written, not yet checked by a person Operation · intersect

Keeps the areas where features of two layers overlap, with the attributes of both.

Pitfall. Overlaps of polygons with lines or points produce lines or points, not polygons.

About this operation
Also called	Pairwise Intersect, Intersection, overlay intersection
Group	`vector/overlay`
Checks	`crs.agreement, geometry.valid, extent.plausible`
Pitfalls	1 listed above
Columbus tool	`vector_op · intersect`
Notes	Not stated
Status	active
Broader	Not stated
Narrower	Not stated
Related	`clip` `spatial-join`

Parameters

Not stated

Inputs and outputs

Direction	Name	Type	Geometry	Note
Input	`a`	vector	Not stated	Not stated
Input	`b`	vector	Not stated	Not stated
Output	`output`	vector	Not stated	Not stated

In each engine

Engine	Tool	Parameters	Differences
`apache-sedona`	`sedona.sql.ST_Intersection`	`a` → `a` `b` → `b`	Per pair of geometries; pairing the features of two tables is a spatial join first. A Spark SQL function: arguments are columns or column names, run over a Spark DataFrame.
`gdal`	`gdal vector layer-algebra`	`a` → `input` `b` → `method` `output` → `output`	The same command also does union, erase, identity, update, clip and symmetric difference by its operation argument. Preset: `{"operation":"intersection"}`
`geopandas`	`geopandas.overlay`	`a` → `df1` `b` → `df2`	keep_geom_type drops results of a different geometry type (lines from polygon overlaps) unless set to false. Preset: `{"how":"intersection"}`
`grass`	`v.overlay`	`a` → `ainput` `b` → `binput` `output` → `output`	The b input must be areas; the same module also does union (or), erase (not) and symmetric difference (xor). Preset: `{"operator":"and"}`
`postgis`	`st_intersection`	`a` → `geom1` `b` → `geom2`	Intersects two geometries; for two layers, join them on ST_Intersects and intersect each matching pair.
`qgis`	`native:intersection`	`a` → `INPUT` `b` → `OVERLAY` `output` → `OUTPUT`	None noted
`sf`	`sf::st_intersection`	`a` → `x` `b` → `y`	With one argument it intersects the features of a single layer with each other.
`shapely`	`shapely.intersection`	`a` → `a` `b` → `b`	Intersects geometries pairwise (or element by element in arrays), not every feature of one layer with every feature of another.
`terra`	`terra::intersect`	`a` → `x` `b` → `y`	None noted
`whiteboxtools`	`Intersect`	`a` → `input` `b` → `overlay` `output` → `output`	None noted