org.opengis.cite.geomatics

Class GeodesyUtils

java.lang.Object

org.opengis.cite.geomatics.GeodesyUtils

public class GeodesyUtils
extends Object

Provides utility methods for using coordinate reference systems and performing coordinate transformations.

Field Summary

Fields

Modifier and Type	Field and Description
static String	EPSG_4326 OGC identifier for WGS 84 (geographic 2D)
static String	OGC_CRS84 OGC identifier for WGS 84 (longitude-latitude)

Constructor Summary

Constructors

Constructor and Description
GeodesyUtils()

Method Summary

Modifier and Type	Method and Description
static DirectPosition	calculateDestination(Position startingPos, double azimuth, double distance) Determines the destination position given the azimuth and distance from some starting position.
static String	convertSRSNameToURN(String srsName) Converts an srsName identifier to the corresponding URN value if it is an 'http' URI.
static String	getAbbreviatedCRSIdentifier(String srsName) Returns an abbreviated identifier for the given CRS reference.
static String	getCRSIdentifier(CoordinateReferenceSystem crs) Returns a well-known identifier (URI) for the given coordinate reference system using the 'urn' scheme (e.g.
static org.geotoolkit.geometry.ImmutableEnvelope	getDomainOfValidity(String crsRef) Returns an immutable envelope representing the valid geographic extent of the CRS identified by the given URI reference.
static void	removeConsecutiveDuplicates(List<com.vividsolutions.jts.geom.Coordinate> coordList, double tolerancePPM) Checks a coordinate list for consecutive duplicate positions and removes them.
static com.vividsolutions.jts.geom.Coordinate[]	transformRingToRightHandedCS(org.geotoolkit.gml.xml.AbstractRing gmlRing) Transforms the given GML ring to a right-handed coordinate system (if it does not already use one) and returns the resulting coordinate sequence.
static com.vividsolutions.jts.geom.Coordinate[]	transformRingToRightHandedCSKeepAllCoords(org.geotoolkit.gml.xml.AbstractRing gmlRing) Transforms the given GML ring to a right-handed coordinate system (if it does not already use one) and returns the resulting coordinate sequence.

Methods inherited from class java.lang.Object

clone, equals, finalize, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Field Detail

EPSG_4326

public static final String EPSG_4326

OGC identifier for WGS 84 (geographic 2D)

See Also:

Constant Field Values

OGC_CRS84

public static final String OGC_CRS84

OGC identifier for WGS 84 (longitude-latitude)

See Also:

Constant Field Values

Constructor Detail

GeodesyUtils

public GeodesyUtils()

Method Detail

getDomainOfValidity

public static org.geotoolkit.geometry.ImmutableEnvelope getDomainOfValidity(String crsRef)
                                                                     throws FactoryException

Returns an immutable envelope representing the valid geographic extent of the CRS identified by the given URI reference.

Parameters:

crsRef - An absolute URI that identifies a CRS definition.

Returns:

An ImmutableEnvelope object.

Throws:

FactoryException - if the CRS reference cannot be resolved to a known definition.

getCRSIdentifier

public static String getCRSIdentifier(CoordinateReferenceSystem crs)

Returns a well-known identifier (URI) for the given coordinate reference system using the 'urn' scheme (e.g. "urn:ogc:def:crs:EPSG::4326").

Parameters:

crs - A CoordinateReferenceSystem object.

Returns:

A String representing a URN value in the 'ogc' namespace; if no identifier can be constructed an empty String is returned.

See Also:

"OGC 09-048r3: Name type specification - definitions - part 1 - basic name"

calculateDestination

public static DirectPosition calculateDestination(Position startingPos,
                                                  double azimuth,
                                                  double distance)

Determines the destination position given the azimuth and distance from some starting position.

Parameters:

startingPos - The starting position.

azimuth - The horizontal angle measured clockwise from a meridian.

distance - The great-circle (orthodromic) distance in the same units as the ellipsoid axis (e.g. meters for EPSG 4326).

Returns:

A DirectPosition representing the destination position (in the same CRS as the starting position).

transformRingToRightHandedCS

public static com.vividsolutions.jts.geom.Coordinate[] transformRingToRightHandedCS(org.geotoolkit.gml.xml.AbstractRing gmlRing)

Transforms the given GML ring to a right-handed coordinate system (if it does not already use one) and returns the resulting coordinate sequence. Many computational geometry algorithms assume right-handed coordinates. In some cases this can be achieved simply by changing the axis order; for example, from (lat,lon) to (lon,lat).

Parameters:

gmlRing - A representation of a GML ring (simple closed curve).

Returns:

A Coordinate[] array, or null if the original CRS could not be identified.

transformRingToRightHandedCSKeepAllCoords

public static com.vividsolutions.jts.geom.Coordinate[] transformRingToRightHandedCSKeepAllCoords(org.geotoolkit.gml.xml.AbstractRing gmlRing)

Transforms the given GML ring to a right-handed coordinate system (if it does not already use one) and returns the resulting coordinate sequence. Many computational geometry algorithms assume right-handed coordinates. In some cases this can be achieved simply by changing the axis order; for example, from (lat,lon) to (lon,lat).

Parameters:

gmlRing - A representation of a GML ring (simple closed curve).

Returns:

A Coordinate[] array, or null if the original CRS could not be identified.

getAbbreviatedCRSIdentifier

public static String getAbbreviatedCRSIdentifier(String srsName)

Returns an abbreviated identifier for the given CRS reference. The result contains the code space (authority) and code value extracted from the URI reference.

Parameters:

srsName - An absolute URI ('http' or 'urn' scheme) that identifies a CRS in accord with OGC 09-048r3.

Returns:

A String of the form "authority:code".

See Also:

OGC 09-048r3, Name type specification - definitions - part 1 - basic name

convertSRSNameToURN

public static String convertSRSNameToURN(String srsName)

Converts an srsName identifier to the corresponding URN value if it is an 'http' URI. The Geotk 3.x library does not recognize CRS identifiers based on the 'http' schreme.

Parameters:

srsName - An absolute URI that identifies a CRS in accord with OGC 09-048r3.

Returns:

A URN-based identifier (the given value is unchanged if it is not an 'http' URI).

See Also:

OGC 09-048r3, Name type specification - definitions - part 1 - basic name

removeConsecutiveDuplicates

public static void removeConsecutiveDuplicates(List<com.vividsolutions.jts.geom.Coordinate> coordList,
                                               double tolerancePPM)

Checks a coordinate list for consecutive duplicate positions and removes them. That is, P(n+1) is removed if it represents the same location as P(n) within the specified tolerance, unless it is the last point in the list in which case P(n) is removed instead (the last point may coincide with the first in order to form a cycle). The third dimension is ignored.

Parameters:

coordList - A list of Coordinate objects.

tolerancePPM - The tolerance for comparing coordinates, in parts per million (ppm).