Top-level functions¶
geoarrow.rust.core ¶
area
builtin
¶
area(input: ArrowArrayExportable) -> Float64Array
Unsigned planar area of a geometry array
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
Float64Array
–Array with area values.
signed_area
builtin
¶
signed_area(input: ArrowArrayExportable) -> Float64Array
Signed planar area of a geometry array
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
Float64Array
–Array with area values.
center
builtin
¶
center(input: ArrowArrayExportable) -> PointArray
Compute the center of geometries
This first computes the axis-aligned bounding rectangle, then takes the center of that box
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
PointArray
–Array with center values.
centroid
builtin
¶
centroid(input: ArrowArrayExportable) -> PointArray
Calculation of the centroid.
The centroid is the arithmetic mean position of all points in the shape. Informally, it is the point at which a cutout of the shape could be perfectly balanced on the tip of a pin.
The geometric centroid of a convex object always lies in the object. A non-convex object might have a centroid that is outside the object itself.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
PointArray
–Array with centroid values.
chaikin_smoothing
builtin
¶
chaikin_smoothing(input: ArrowArrayExportable, n_iterations: int) -> LineStringArray | PolygonArray | MultiLineStringArray | MultiPolygonArray
Smoothen LineString
, Polygon
, MultiLineString
and MultiPolygon
using Chaikins algorithm.
Each iteration of the smoothing doubles the number of vertices of the geometry, so in some cases it may make sense to apply a simplification afterwards to remove insignificant coordinates.
This implementation preserves the start and end vertices of an open linestring and smoothes the corner between start and end of a closed linestring.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
-
n_iterations
(int
) –Number of iterations to use for smoothing.
Returns:
-
LineStringArray | PolygonArray | MultiLineStringArray | MultiPolygonArray
–Smoothed geometry array.
chamberlain_duquette_unsigned_area
builtin
¶
chamberlain_duquette_unsigned_area(input: ArrowArrayExportable) -> Float64Array
Calculate the unsigned approximate geodesic area of a Geometry
.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
Float64Array
–Array with area values.
chamberlain_duquette_signed_area
builtin
¶
chamberlain_duquette_signed_area(input: ArrowArrayExportable) -> Float64Array
Calculate the signed approximate geodesic area of a Geometry
.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
Float64Array
–Array with area values.
convex_hull
builtin
¶
convex_hull(input: ArrowArrayExportable) -> PolygonArray
Returns the convex hull of a Polygon. The hull is always oriented counter-clockwise.
This implementation uses the QuickHull algorithm, based on Barber, C. Bradford; Dobkin, David P.; Huhdanpaa, Hannu (1 December 1996) Original paper here: www.cs.princeton.edu/~dpd/Papers/BarberDobkinHuhdanpaa.pdf
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
PolygonArray
–Array with convex hull polygons.
densify
builtin
¶
densify(input: ArrowArrayExportable, max_distance: float) -> LineStringArray | PolygonArray | MultiLineStringArray | MultiPolygonArray
Return a new linear geometry containing both existing and new interpolated
coordinates with a maximum distance of max_distance
between them.
Note: max_distance
must be greater than 0.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
-
max_distance
(float
) –maximum distance between coordinates
Returns:
-
LineStringArray | PolygonArray | MultiLineStringArray | MultiPolygonArray
–Densified geometry array
envelope
builtin
¶
envelope(input: ArrowArrayExportable) -> RectArray
Computes the minimum axis-aligned bounding box that encloses an input geometry
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
RectArray
–Array with axis-aligned bounding boxes.
is_empty
builtin
¶
is_empty(input: ArrowArrayExportable) -> BooleanArray
Returns True if a geometry is an empty point, polygon, etc.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
BooleanArray
–Result array.
geodesic_area_signed
builtin
¶
geodesic_area_signed(input: ArrowArrayExportable) -> Float64Array
Determine the area of a geometry on an ellipsoidal model of the earth.
This uses the geodesic measurement methods given by Karney (2013).
Assumptions¶
- Polygons are assumed to be wound in a counter-clockwise direction for the exterior ring and a clockwise direction for interior rings. This is the standard winding for geometries that follow the Simple Feature standard. Alternative windings may result in a negative area. See "Interpreting negative area values" below.
- Polygons are assumed to be smaller than half the size of the earth. If you expect to be dealing
with polygons larger than this, please use the
unsigned
methods.
Units¶
- return value: meter²
Interpreting negative area values¶
A negative value can mean one of two things:
1. The winding of the polygon is in the clockwise direction (reverse winding). If this is the case, and you know the polygon is smaller than half the area of earth, you can take the absolute value of the reported area to get the correct area.
2. The polygon is larger than half the planet. In this case, the returned area of the polygon is not correct. If you expect to be dealing with very large polygons, please use the unsigned
methods.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
Float64Array
–Array with output values.
geodesic_area_unsigned
builtin
¶
geodesic_area_unsigned(input: ArrowArrayExportable) -> Float64Array
Determine the area of a geometry on an ellipsoidal model of the earth. Supports very large geometries that cover a significant portion of the earth.
This uses the geodesic measurement methods given by Karney (2013).
Assumptions¶
- Polygons are assumed to be wound in a counter-clockwise direction for the exterior ring and a clockwise direction for interior rings. This is the standard winding for geometries that follow the Simple Features standard. Using alternative windings will result in incorrect results.
Units¶
- return value: meter²
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
Returns:
-
Float64Array
–Array with output values.
geodesic_perimeter
builtin
¶
geodesic_perimeter(input: ArrowArrayExportable) -> Float64Array
Determine the perimeter of a geometry on an ellipsoidal model of the earth.
This uses the geodesic measurement methods given by Karney (2013).
For a polygon this returns the sum of the perimeter of the exterior ring and interior rings.
To get the perimeter of just the exterior ring of a polygon, do polygon.exterior().geodesic_length()
.
Units¶
- return value: meter
Returns:
-
Float64Array
–Array with output values.
simplify
builtin
¶
simplify(input: ArrowArrayExportable, epsilon: float) -> PointArray | LineStringArray | PolygonArray | MultiPointArray | MultiLineStringArray | MultiPolygonArray
Simplifies a geometry.
The Ramer–Douglas–Peucker algorithm simplifies a linestring. Polygons are simplified by running the RDP algorithm on all their constituent rings. This may result in invalid Polygons, and has no guarantee of preserving topology.
Multi* objects are simplified by simplifying all their constituent geometries individually.
An epsilon less than or equal to zero will return an unaltered version of the geometry.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
-
epsilon
(float
) –tolerance for simplification.
Returns:
-
PointArray | LineStringArray | PolygonArray | MultiPointArray | MultiLineStringArray | MultiPolygonArray
–Simplified geometry array.
simplify_vw
builtin
¶
simplify_vw(input: ArrowArrayExportable, epsilon: float) -> PointArray | LineStringArray | PolygonArray | MultiPointArray | MultiLineStringArray | MultiPolygonArray
Returns the simplified representation of a geometry, using the Visvalingam-Whyatt algorithm
See here for a graphical explanation
Polygons are simplified by running the algorithm on all their constituent rings. This may result in invalid Polygons, and has no guarantee of preserving topology. Multi* objects are simplified by simplifying all their constituent geometries individually.
An epsilon less than or equal to zero will return an unaltered version of the geometry.
Parameters:
-
input
(ArrowArrayExportable
) –input geometry array
-
epsilon
(float
) –tolerance for simplification.
Returns:
-
PointArray | LineStringArray | PolygonArray | MultiPointArray | MultiLineStringArray | MultiPolygonArray
–Simplified geometry array.