Geometry Class
Base class for classes that represent geometric shapes. More...
| Header: | #include <Geometry.h> |
| Since: | Esri::ArcGISRuntime 100.0 |
| Inherits: | Esri::ArcGISRuntime::JsonSerializable |
| Inherited By: | Esri::ArcGISRuntime::Envelope, Esri::ArcGISRuntime::Multipart, Esri::ArcGISRuntime::Multipoint, and Esri::ArcGISRuntime::Point |
Public Functions
| Geometry(Esri::ArcGISRuntime::Geometry &&other) | |
| Geometry(const Esri::ArcGISRuntime::Geometry &other) | |
| Geometry() | |
| Esri::ArcGISRuntime::Geometry & | operator=(Esri::ArcGISRuntime::Geometry &&other) |
| Esri::ArcGISRuntime::Geometry & | operator=(const Esri::ArcGISRuntime::Geometry &other) |
| virtual | ~Geometry() override |
| Esri::ArcGISRuntime::GeometryDimension | dimension() const |
| bool | equalsWithTolerance(const Esri::ArcGISRuntime::Geometry &other, double tolerance) const |
| Esri::ArcGISRuntime::Envelope | extent() const |
| Esri::ArcGISRuntime::GeometryType | geometryType() const |
| bool | hasCurves() const |
| bool | hasM() const |
| bool | hasZ() const |
| bool | isEmpty() const |
| Esri::ArcGISRuntime::SpatialReference | spatialReference() const |
| bool | operator==(const Esri::ArcGISRuntime::Geometry &other) const |
Reimplemented Public Functions
| virtual QString | toJson() const override |
| virtual QJsonObject | unknownJson() const override |
| virtual QJsonObject | unsupportedJson() const override |
Static Public Members
| Esri::ArcGISRuntime::Geometry | fromJson(const QString &json) |
Detailed Description
Geometry is the base class for two-dimensional (x,y) or three-dimensional (x,y,z) geometries. Objects that inherit from the Geometry class may also include a measure (m-value) for each vertex. The Geometry class provides functionality common to all types of geometry. Point, Multipoint, Polyline, Polygon, and Envelope all inherit from Geometry and represent different types of shapes.
Geometry represents real-world objects by defining a shape at a specific geographic location. It is used throughout this API to represent the shapes of features and graphics, layer extents, viewpoints, and GPS locations. It is also used, for example, to define inputs and outputs for spatial analysis and geoprocessing operations and to measure distances and areas.
All types of geometry:
- Have a SpatialReference indicating the coordinate system used by its coordinates
- Can be empty, indicating that they have no specific location or shape
- May have z-values and/or m-values to define elevation and measures respectively
- Can be converted to and from JSON to be persisted or to be exchanged directly with REST services
Immutability
Most geometries are created and not changed for their lifetime. Examples include features created to be stored in a geodatabase or read from a non-editable layer, and features returned from tasks such as a spatial query, geocode operation, network trace, or geoprocessing task. Immutable geometries (geometries that cannot be changed) offer some important benefits to your app. They are inherently thread-safe, help prevent inadvertent changes, and allow for certain performance optimizations.
Instead of changing the properties of existing geometries, you can create and update geometries using the various subclasses of GeometryBuilder (for example, PolygonBuilder), which can represent the state of a geometry under construction while allowing modifications, thus enabling editing workflows.
Additionally, GeometryEngine offers a range of topological and spatial transformations that read the content of existing geometries and create new geometries, for example, project, buffer, union, and so on. Relational tests such as intersects and overlaps are also available on GeometryEngine.
Coordinate units
The coordinates that define a geometry are only meaningful in the context of the geometry's SpatialReference. The vertices and spatial reference together allow your app to translate a real-world object from its location on the Earth to its location on your map or scene.
In some cases, a geometry's spatial reference may not be set. For example, a Graphic that does not have a spatial reference is drawn using the same spatial reference as the MapView to which it was added. If the coordinates are in a different spatial reference, the graphics may not display in the correct location, or at all.
When using GeometryBuilder to create a Polyline or Polygon from a collection of Point, you don't need to set the spatial reference of every point before you add it to the builder, as it is assigned the spatial reference of the builder itself. In most other cases, such as when using a geometry in geometry operations or when editing a feature table, spatialReference must be set.
Spatial reference and projection
Changing the coordinates of a geometry to have the same shape and location represented using a different SpatialReference is known as "projection" or sometimes as "reprojection". Because geometries are immutable, they do not have any member methods that project, transform, or otherwise modify their content.
See also GeometryEngine, GeometryBuilder, and GeometryEditor.
Member Function Documentation
Geometry::Geometry(Esri::ArcGISRuntime::Geometry &&other)
Move constructor from other Geometry.
Geometry::Geometry(const Esri::ArcGISRuntime::Geometry &other)
Copy constructor from other Geometry.
Geometry::Geometry()
Default constructor. Creates an empty Geometry.
Esri::ArcGISRuntime::Geometry &Geometry::operator=(Esri::ArcGISRuntime::Geometry &&other)
Move operator from other Geometry.
Esri::ArcGISRuntime::Geometry &Geometry::operator=(const Esri::ArcGISRuntime::Geometry &other)
Assignment operator from other Geometry.
[override virtual] Geometry::~Geometry()
Destructor.
Esri::ArcGISRuntime::GeometryDimension Geometry::dimension() const
Returns the number of dimensions for the geometry.
Every non-empty Geometry has an inherent dimension (sometimes called the topological dimensionality) that indicates the general class of the Geometry.
Returns GeometryDimension::Unknown if an error occurs.
See also GeometryDimension.
bool Geometry::equalsWithTolerance (const Esri::ArcGISRuntime::Geometry &other, double tolerance) const
Returns whether this object and other are equal within the tolerance.
Esri::ArcGISRuntime::Envelope Geometry::extent() const
Returns the smallest rectangular bounding-box that covers the geometry.
[static] Esri::ArcGISRuntime::Geometry Geometry::fromJson (const QString &json)
Creates this geometry from an ArcGIS json geometry representation.
Returns a Geometry created using the data in the json parameter.
Esri::ArcGISRuntime::GeometryType Geometry::geometryType () const
Gets the geometry type.
Returns the geometry type enumeration.
bool Geometry::hasCurves () const
Returns true if this geometry contains curve segments; false otherwise.
ArcGIS software supports polygon and polyline geometries that contain curve segments (where Segment::isCurve is true, 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 true curves, this API retrieves densified versions of curve feature geometries by default.
If a polygon or polyline geometry contains curve segments, this property returns true. Prior to Esri::ArcGISRuntime 100.12, it was not possible to access curve segments, and only LineSegment instances would be returned when iterating through the segments in a Polygon or Polyline object, regardless of this property.
From Esri::ArcGISRuntime 100.12, you can use curve segments when using a MultipartBuilder to create or edit polygon and polyline geometries, and also get curve segments when iterating through the segments of existing Multipart geometries when this property returns true.
You can also choose to return true curves from feature services by using ArcGISRuntimeEnvironment::serviceCurveGeometryMode.
bool Geometry::hasM () const
Returns true if this geometry contains m-values (measure values).
bool Geometry::hasZ () const
Returns true if this geometry contains z-coordinate values.
Only 3D geometries contain z-coordinate values.
bool Geometry::isEmpty () const
Gets whether this Geometry is empty.
A Geometry is empty if it does not contain any valid geographic coordinates. If a SpatialReference was specified, but still no valid coordinates exist, then the Geometry is still empty.
Returns true if empty.
Esri::ArcGISRuntime::SpatialReference Geometry::spatialReference () const
Gets the SpatialReference of the Geometry.
Returns the spatial reference of the coordinates assigned to the Geometry.
[override virtual] QString Geometry::toJson () const
Reimplements: JsonSerializable::toJson() const.
Converts a geometry into an ArcGIS json geometry representation.
Returns this Geometry represented as a JSON String.
[override virtual] QJsonObject Geometry::unknownJson () const
Reimplements: JsonSerializable::unknownJson() const.
Gets the unknown JSON of this object.
See also JsonSerializable.
[override virtual] QJsonObject Geometry::unsupportedJson () const
Reimplements: JsonSerializable::unsupportedJson() const.
Gets the unsupported JSON of this object.
See also JsonSerializable.
bool Geometry::operator==(const Esri::ArcGISRuntime::Geometry &other) const
Equivalency operator.
Returns whether this object and other are equivalent.