Package com.esri.arcgisruntime.geometry

Class HorizontalVerticalTransformationStep

  • public final class HorizontalVerticalTransformationStep
extends Object
    Represents a step in the process of transforming between horizontal and/or vertical datums.

    A horizontal-vertical transformation step can be constructed from a well-known ID (WKID) that represents a known horizontal (geographic) or vertical transformation, using the create(int) factory method. Alternatively, a custom transformation can be constructed from well-known text using create(String). After creating a HorizontalVerticalTransformationStep, one or more steps can be added to a HorizontalVerticalTransformation, and used to project a Geometry. 

    // Create a 3D geometry located in London, UK, with British National Grid spatial reference with Newlyn
 // vertical coordinate system
 Point britishNationalGrid3dPt = new Point(538985.355, 177329.516, 154.0, SpatialReference.create(27700, 5701));

 // Project the point to WGS84, with WG84 ellipsoidal vertical coordinate system, using the transformation
 SpatialReference wgsVcsSr = SpatialReference.create(4326, 115700)
 Point wgs84Pt = (Point) GeometryEngine.project(britishNationalGrid3dPt, wgsVcsSr, transform);

    This SDK supports thousands of horizontal and vertical transformation WKIDs, which are documented in the developer Guide on the ArcGIS for Developers site.

    Alternatively, horizontal-vertical transformations can be created by using the methods on TransformationCatalog.

    Some transformations rely on supporting files to be present in a known location (see TransformationCatalog.getProjectionEngineDirectory()). Use isMissingProjectionEngineFiles() to identify transformations for which the supporting files are missing. If true, then the transformation cannot be used to project geometries. Use getProjectionEngineFilenames() to identify which files are missing for this step.

    Horizontal-vertical transformation steps are immutable. Use getInverse() to get a new step representing the same transformation in the opposite direction.

    Since:
    100.9.0
    See Also:
    HorizontalVerticalTransformation, GeographicTransformationStep, GeometryEngine.project(Geometry, SpatialReference, DatumTransformation)

    • Method Detail

      • create

        public static HorizontalVerticalTransformationStep create​(int wkid)
        Creates a HorizontalVerticalTransformationStep instance from the given well-known ID (WKID).

        If the WKID defines a grid-based transformation, the transformation can only be used if the supporting files are found on the local file system. See isMissingProjectionEngineFiles().

        Occasionally, WKIDs may change, and older codes may be deprecated in favor of a new code. Both old (deprecated) and new (latest) WKIDs continue to work for instantiation, as long as they are supported by the Projection Engine. The getWkid() property will return the new (latest) WKID code.

        Parameters:
        wkid - a WKID of the horizontal-vertical transformation step to create
        Returns:
        a HorizontalVerticalTransformationStep instance
        Throws:
        ArcGISRuntimeException - if wkid is invalid (is not a supported WKID). The list of supported WKIDs is documented in the developer Guide.
        Since:
        100.9.0
        See Also:
        getWkid()

      • create

        public static HorizontalVerticalTransformationStep create​(String wkText)
        Creates a HorizontalVerticalTransformationStep instance from the given well-known text (WKT) string.

        Some users adjust the components of a transformation to suit their specific needs. These custom transformations use the existing methods of transformation (Position Vector, Geocentric_Translation, and so on) but have different parameter values than the well-known definitions. Create a custom horizontal-vertical transformation object by passing in a text string containing your custom transformation expressed in WKT format. The resulting transformation will have a WKID of zero.

        If the WKT defines a grid-based transformation, the transformation can only be used if the supporting files are found on the local file system. See isMissingProjectionEngineFiles().

        Parameters:
        wkText - a string containing a WKT representation of a HorizontalVerticalTransformationStep
        Returns:
        a HorizontalVerticalTransformationStep instance
        Throws:
        IllegalArgumentException - if wkText is null or empty
        ArcGISRuntimeException - if wkText is invalid (is not a well-formed transformation text string)
        Since:
        100.9.0
        See Also:
        getWkText()

      • getInverse

        public HorizontalVerticalTransformationStep getInverse()
        Gets the inverse of this horizontal-vertical transformation step.

        The inverse of a transformation converts coordinates using the same method and parameters, but in the opposite direction of the original object. For example if the original object represents NAD_1983_HARN_To_NAD_1983_NSRS2007_1 transformation, then the inverse will transform from NAD83 (NSRS 2007) to NAD83 (HARN).

        To check the input and output SpatialReferences of a transformation step, add the step to a new HorizontalVerticalTransformation, and check DatumTransformation.getInputSpatialReference() and DatumTransformation.getOutputSpatialReference().

        Returns:
        the inverse of this horizontal-vertical transformation step or null if the transformation is not invertible
        Since:
        100.9.0

      • getWkText

        public String getWkText()
        Gets a string containing the well-known text representation of this HorizontalVerticalTransformationStep.
        Returns:
        a well-known text representation of this HorizontalVerticalTransformationStep
        Since:
        100.9.0

      • getWkid

        public int getWkid()
        Gets the well-known ID (WKID) representation of this HorizontalVerticalTransformationStep.

        The list of supported WKIDs is documented in the developer Guide.

        Occasionally, WKIDs may change, and an older code may be deprecated in favor of a new code. This property returns the new (latest) WKID code.

        Returns:
        a WKID representation of this HorizontalVerticalTransformationStep, or 0 if this transformation was created from a custom well-known text string, -1 on error.
        Since:
        100.9.0

      • isInverse

        public boolean isInverse()
        Indicates if this transformation step instance is an inverted transformation.

        Transformations have a specific direction that is indicated by the getWkText() value. An inverted transformation is used to transform geometries in the opposite direction to that indicated by the Well-Known Text. The GeographicTransformation has DatumTransformation.getInputSpatialReference() and DatumTransformation.getOutputSpatialReference() properties that respect the inverse value of the contained transformation(s).

        Returns:
        true if this transformation step instance is an inverted transformation; false otherwise
        Since:
        100.9.0

      • isMissingProjectionEngineFiles

        public boolean isMissingProjectionEngineFiles()
        Indicates if any files needed by the Projection Engine for this horizontal-vertical transformation step are missing from the local file system.

        If true, this indicates that this transformation step is not currently usable; in this case, using the GeometryEngine.project(Geometry, SpatialReference, DatumTransformation) method with a transform including this step will throw an exception. In order for a transform step to be usable, two conditions must be satisfied:

        • In order for any Projection Engine files to be found, the root directory must have been successfully set before any transforms are used, using TransformationCatalog.setProjectionEngineDirectory(String). For Java SE, if the default Projection Engine directory is found during Runtime initialization, explicitly setting the location is not required.
        • The specific Projection Engine files required by this step must be found within the Projection Engine directory. Use getProjectionEngineFilenames() to find out the filenames required by this step.

        If Projection Engine files are installed at run time, the app will need to be restarted for this value to change.

        Returns:
        true if any required files are missing; false otherwise
        Since:
        100.9.0

      • getProjectionEngineFilenames

        public List<String> getProjectionEngineFilenames()
        Gets the filenames that comprise the supporting dataset for this transformation.

        Projection Engine datasets are used by grid-based transformations; equation-based transformations do not require any supporting files.

        Each filename includes the path relative to TransformationCatalog.getProjectionEngineDirectory(), indicating the subdirectory (or directories) and the filename including extension.

        Returns:
        an unmodifiable List of the filenames that comprise the supporting dataset, or an empty List if this step does not require supporting files (is an equation-based transformation).
        Since:
        100.9.0

      • equals

        public boolean equals​(Object obj)
        Indicates whether some other object is "equal to" this HorizontalVerticalTransformationStep. Returns true if the two transformation steps use the same method of transformation, and operate in the same direction.
        Overrides:
        equals in class Object
        Parameters:
        obj - the reference HorizontalVerticalTransformationStep with which to compare
        Returns:
        true if this object has the same values as the obj argument; false otherwise
        Since:
        100.9.0

      • hashCode

        public int hashCode()
        Overrides:
        hashCode in class Object