ArcGIS Runtime SDK for iOS: AGSGeographicTransformationStep Class Reference
ArcGIS Runtime SDK for iOS  100.14
AGSGeographicTransformationStep Class Reference

Description

Represents a step in the process of transforming between datums.

Instances of this class represent a step in the process of transforming between datums of spatial references.

Each geographic transformation step can be constructed from a well-known ID (WKID) that represents a geographic transformation. Because the Projection Engine supports thousands of transformations, WKIDs are not presented in the SDK as enumerations. Instead, they are documented in the developers guide.

The list of supported WKIDs includes a transformation from every supported datum to WGS 1984. Additionally, there is a more limited list of transformations directly between two non-WGS84 datums, such as 4461, which is NAD_1983_HARN_To_NAD_1983_NSRS2007_1.

Transformations with more than one step typically go via WGS84, with one forward and one inverse geographic transformation chained together to get the required geographic coordinates.

A geographic transformation step object is immutable.

See also
AGSTransformationCatalog to find a list of suitable tranformations between two spatial references
AGSGeographicTransformation, AGSHorizontalVerticalTransformationStep
Since
100.2
Inheritance diagram for AGSGeographicTransformationStep:
AGSObject

Instance Methods

(nullable instancetype) - initWithWKID:
 
(nullable instancetype) - initWithWKText:
 
(nullable AGSGeographicTransformationStep *) - inverse
 
(BOOL) - isEqualToGeographicTransformationStep:
 

Class Methods

(nullable instancetype) + geographicTransformationStepWithWKID:
 
(nullable instancetype) + geographicTransformationStepWithWKText:
 

Properties

BOOL inverse
 
BOOL missingProjectionEngineFiles
 
NSArray< NSString * > * projectionEngineFilenames
 
NSInteger WKID
 
NSString * WKText
 

Method Documentation

◆ geographicTransformationStepWithWKID:

+ (nullable instancetype) geographicTransformationStepWithWKID: (NSInteger)  WKID

Initialize this step with the given well-known ID of a geographic transformation.

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 AGSGeographicTransformationStep::WKID property will return the new (latest) WKID code.

Parameters
WKIDwell-known ID of a geographic transformation.
Returns
Initialized geographic transformation step.
Since
100.2

◆ geographicTransformationStepWithWKText:

+ (nullable instancetype) geographicTransformationStepWithWKText: (NSString *)  WKText

Initialize this step with the given well-known text of a geographic transformation.

Parameters
WKTextwell-known text of a geographic transformation.
Returns
Initialized geographic transformation step.
Since
100.2

◆ initWithWKID:

- (nullable instancetype) initWithWKID: (NSInteger)  WKID

Initialize this step with the given well-known ID of a geographic transformation.

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 AGSGeographicTransformationStep::WKID property will return the new (latest) WKID code.

Parameters
WKIDwell-known ID of a geographic transformation.
Returns
Initialized geographic transformation step.
Since
100.2

◆ initWithWKText:

- (nullable instancetype) initWithWKText: (NSString *)  WKText

Initialize this step with the given well-known text of a geographic transformation.

Parameters
WKTextwell-known text of a geographic transformation.
Returns
Initialized geographic transformation step.
Since
100.2

◆ inverse

- (nullable AGSGeographicTransformationStep*) inverse

Returns the inverse of this geographic transformation step or NULL if the transformation is not invertible.

Since
100.2

◆ isEqualToGeographicTransformationStep:

- (BOOL) isEqualToGeographicTransformationStep: (AGSGeographicTransformationStep *)  other

Returns if this geographic transformation step is equal to the one provided

Parameters
otherstep to compare this one to
Since
100.2

Property Documentation

◆ inverse

- (BOOL) inverse
readnonatomicassign

YES if this geographic transformation step instance is an inverted transformation.

Transformations have a specific direction that is indicated by the AGSGeographicTransformationStep::WKText value. An inverted transformation is used to transform geometries in the opposite direction to that indicated by the well-known text. AGSGeographicTransformation has AGSDatumTransformation::inputSpatialReference and AGSDatumTransformation::outputSpatialReference properties that respect the inverse value of the contained transformation(s).

ArcGIS Runtime supports a large number of transformation WKIDs, including transformations from every supported datum to the World Geodetic System 1984 (WGS84) datum. To transform coordinates between two non-WGS84 datums, typically one forward and one inverse AGSGeographicTransformationStep are added to an AGSGeographicTransformation, to get the required inputs and outputs.

See also
AGSGeographicTransformationStep::inverse
Since
100.10

◆ missingProjectionEngineFiles

- (BOOL) missingProjectionEngineFiles
readnonatomicassign

Indicates if any files needed by the Projection Engine for this geographic transformation step are missing from the local file system

Note
In order for the Projection Engine files to be found, their location must be set upon application startup using setProjectionEngineDirectory:error: (AGSTransformationCatalog) before using any other Runtime API.
Since
100.2

◆ projectionEngineFilenames

- (NSArray<NSString*>*) projectionEngineFilenames
readnonatomiccopy

The list of the Projection Engine files required to support this geographic transformation step. Each name in the list includes the full path. Projection Engine datasets are used in grid-based transforms.

Note
In order for the Projection Engine files to be found, their location must be set upon application startup using setProjectionEngineDirectory:error: (AGSTransformationCatalog) before using any other Runtime API.
Since
100.2

◆ WKID

- (NSInteger) WKID
readnonatomicassign

The well-known ID or 0 if the transformation in this step doesn't have a well-known ID.

-1 on error.

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.

Since
100.2

◆ WKText

- (NSString*) WKText
readnonatomiccopy

The well-known text of this geographic transformation step instance.

This value does not respect the AGSGeographicTransformationStep::inverse property.

Since
100.2