AGSPolygon Class Reference

Description

A multipart shape used to represent an area.

Polygon geometries represent the shape and location of areas, for example, a country, island, or a lake. A polygon can be used as the geometry of features and graphics, or as input or output of tasks or geoprocessing operations, such as the output of a drive-time analysis or an AGSGeometryEngine::bufferWithGeometry:distance: operation.

Each part of a multipart polygon is a series of connected AGSSegment objects forming a closed ring. Each part must not cross any other part, but may lie completely inside or outside another part. For example, a polygon representing the state of Hawaii would comprise eight disjoint parts, one representing each island. A polygon representing the country of South Africa, which completely surrounds the enclave of Lesotho, would comprise two parts, one contained inside the other.

Like polyline, the polygon class is an AGSMultipart, which provides members for iterating the segments and points of each part in a polygon. Unlike parts in a polyline, however, each part of a polygon defines a closed area, so the end point of the last segment in the part is always in the same location as the start point of the first segment, forming a closed boundary.

When defining a polygon part, there is no need to explicitly close it by repeating the start point as the last point. Polygons parts are always interpreted as enclosed areas by ArcGIS Runtime.

Interior rings to make donut polygons should be counter-clockwise in direction to have the correct topology.

If there is ever a doubt about the topological correctness of a polygon, call the AGSGeometryEngine::simplifyWithGeometry: method to correct any issues. This is especially true if you pass a polygon to ArcGIS Server for a geoprocessing task to avoid any ArcGIS Server errors being thrown or to rectify polygons that may be self-intersecting, have rings which are partially contained in each other, or contain incorrect ring orientations.

Polygons are based upon the parent AGSGeometry class. The geometry object is immutable which means that you can not change its shape once it is created. If you need to create a new polygon or modify it once it has been created, use the AGSPolygonBuilder class.

A polygon can be used as the geometry of an AGSFeature or AGSGraphic. To obtain the geometry on these objects, use AGSGeoElement::geometry.

See also

AGSPolygonBuilder to construct or modify polygons programmatically.

AGSSketchEditor to construct or modify geometries interactively by sketching on a map.

AGSGeometryEngine to perform operations on geometries.

Inheritance diagram for AGSPolygon:

Instance Methods
(BOOL)	- isEqualToGeometry:
(BOOL)	- isEqualToGeometry:
(BOOL)	- isEqualToGeometry:tolerance:
(AGSPolygonBuilder *)	- toBuilder
(nullable id)	- toJSON:
(AGSPolyline *)	- toPolyline

Class Methods
(nullable id< AGSJSONSerializable >)	+ fromJSON:error:
(instancetype)	+ polygonWithPoints:

Properties
AGSGeometryDimension	dimension
BOOL	empty
AGSEnvelope *	extent
AGSGeometryType	geometryType
BOOL	hasCurves
BOOL	hasM
BOOL	hasZ
AGSPartCollection *	parts
AGSSpatialReference *	spatialReference
NSDictionary< NSString *, id > *	unknownJSON
NSDictionary< NSString *, id > *	unsupportedJSON

Method Documentation

fromJSON:error:

+ (nullable id<AGSJSONSerializable>) fromJSON: (id)  JSONObject error: (NSError **)  error

staticrequiredinherited

Initializes and returns an object from its JSON representation.

Parameters

JSONObject	NSDictionary or NSArray containing the JSON.
error	encountered during the operation, if any.

Since

100

isEqualToGeometry: [1/2]

- (BOOL) isEqualToGeometry:

(AGSGeometry *)

other

Compares whether two geometries are equal.

Parameters

other

The other geometry object to compare this geometry object to.

Returns

YES if the geometries are equal.

Since

100

isEqualToGeometry: [2/2]

- (BOOL) isEqualToGeometry:

(AGSPolygon *)

other

Compares whether two polygon geometries are equal.

Parameters

other

polygon to compare this polygon to

Returns

YES if the polygons are equal

Since

100

isEqualToGeometry:tolerance:

- (BOOL) isEqualToGeometry:		(AGSGeometry *)	other
tolerance:		(double)	tolerance

Compares two geometry objects for equality to within some tolerance.

Parameters

other	The other geometry object to compare this geometry object to.
tolerance	The tolerance.

Returns

YES if the geometries are equal within the given tolerance, otherwise NO.

Since

100

polygonWithPoints:

+ (instancetype) polygonWithPoints:

(NSArray< AGSPoint * > *)

points

Initializes a polygon.

Parameters

points

for the geometry to be constructed

Since

100

toBuilder

- (AGSPolygonBuilder*) toBuilder

Returns a builder using a copy of this geometry as a starting off point. The builder can then be modified to produce a new geometry.

Returns

builder that can be used to build polygon geometries.

Since

100

Note

Operations on the builder affect only its own internal copy of the geometry. They do not affect this geometry.

Implements AGSGeometry.

toJSON:

- (nullable id) toJSON: (NSError **)  error

requiredinherited

Returns JSON representation for this object.

Parameters

error

encountered during the operation, if any.

Returns

NSDictionary or NSArray containing the JSON.

Since

100

Reimplemented in AGSPortalItem.

toPolyline

- (AGSPolyline*) toPolyline

Property Documentation

dimension

- (AGSGeometryDimension) dimension

readnonatomicassigninherited

The dimension of this geometry object.

Note

The property will be AGSGeometryDimension::AGSGeometryDimensionUnknown if an error occurs.

Since

100

empty

- (BOOL) empty

readnonatomicassigninherited

Indicates whether this geometry has any vertices.

Since

100

extent

- (AGSEnvelope*) extent

readnonatomicstronginherited

Smallest, rectangular bounding-box that covers the geometry.

Since

100

geometryType

- (AGSGeometryType) geometryType

readnonatomicassigninherited

The type of this geometry.

Since

100

hasCurves

- (BOOL) hasCurves

readnonatomicassigninherited

YES if this geometry contains curve segments, NO otherwise.

The ArcGIS Platform supports polygon and polyline geometries that contain curve segments (where AGSSegment::curve is YES, sometimes known as true curves or nonlinear segments). Curves may be present in certain types of data - for example Mobile Map Packages (MMPK) or geometry JSON. When connecting to ArcGIS feature services that support curves (AGSArcGISFeatureServiceInfo::supportsTrueCurve), ArcGIS Runtime retrieves densified versions of curve feature geometries by default.

If a polygon or polyline geometry contains curve segments, this property is YES. Prior to v100.12, it was not possible to access curve segments, and only AGSLineSegment instances would be returned when iterating through the segments in an AGSPolygon or AGSPolyline object, irrespective of this property.

From v100.12, you can use curve segments when using an AGSMultipartBuilder to create or edit polygon and polyline geometries, and also get curve segments when iterating through the segments of existing AGSMultipart geometries when this property returns YES. You can also choose to return true curves from feature services by using AGSArcGISRuntimeEnvironment::serviceCurveGeometryMode.

See also

AGSGeometryBuilder::hasCurves, AGSPart::hasCurves, AGSSegment::curve, AGSCubicBezierSegment, AGSEllipticArcSegment

Since

100

hasM

- (BOOL) hasM

readnonatomicassigninherited

Indicates whether this geometry contains m (measure) values.

Since

100

hasZ

- (BOOL) hasZ

readnonatomicassigninherited

Indicates whether this geometry contains z coordinate values. Only 3D geometries contain z values.

Since

100

parts

- (AGSPartCollection*) parts

readnonatomicstronginherited

The parts of this geometry.

Can be iterated through a for-in loop.

AGSPolygon* polygon = ... ; //polygon with 2 parts (rings)
for (AGSPart* part in polygon.parts) {
  ...
}

Since

100

spatialReference

- (AGSSpatialReference*) spatialReference

readnonatomicstronginherited

The spatial reference associated with the gometry. It specifies the coordinate system for the geometry's x, y, and z coordinate values.

Since

100

Note

Geometries that represent geographic locations should always have a spatial reference. Otherwise the coordinates of the geometry are meaningless.

unknownJSON

- (NSDictionary<NSString*,id>*) unknownJSON

readrequirednonatomiccopyinherited

A dictionary of values that was in the source JSON but was unparsed by API.

Returns

NSDictionary containing the unknown JSON.

Since

100

unsupportedJSON

- (NSDictionary<NSString*,id>*) unsupportedJSON

readnonatomiccopyinherited

A dictionary of values that are supported by the REST API, but not exposed through the SDK API.

Returns

NSDictionary containing the unsupported JSON.

Since

100