Count Points In Polygon

Draft: written, not yet checked by a person Operation · count-points-in-polygon

Adds to each polygon the number of points that fall inside it.

Pitfall. Points exactly on a shared boundary are counted in both polygons by some engines and in one by others.

About this operation
Also called	point count, points in polygons, Summarize Within (count)
Group	`vector/joins`
Checks	`crs.agreement, join.unmatched`
Pitfalls	1 listed above
Columbus tool	Not stated
Notes	Not stated
Status	active
Broader	Not stated
Narrower	Not stated
Related	`spatial-join` `zonal-statistics`

Parameters

Name	Type	Required	Default	Values	Note
`field`	string	no	Not stated	Not stated	Name of the new count attribute.

Direction	Name	Type	Geometry	Note
Input	`polygons`	vector	polygon	Not stated
Input	`points`	vector	point	Not stated
Output	`output`	vector	polygon	Not stated

Engine	Tool	Parameters	Differences
`grass`	`v.vect.stats`	`field` → `count_column` `polygons` → `areas` `points` → `points`	Writes the count into the areas map's own attribute table; there is no separate output. method and stats_column add other statistics of a points column.
`qgis`	`native:countpointsinpolygon`	`field` → `FIELD` `polygons` → `POLYGONS` `points` → `POINTS` `output` → `OUTPUT`	CLASSFIELD counts distinct values of a field instead; WEIGHT sums a field.