org.geotools.referencing.operation.projection

Class IdrTransverseMercator

java.lang.Object

MapProjection

org.geotools.referencing.operation.projection.IdrTransverseMercator

public class IdrTransverseMercator
extends MapProjection

Transverse Mercator Projection (EPSG code 9807). This is a cylindrical projection, in which the cylinder has been rotated 90. Instead of being tangent to the equator (or to an other standard latitude), it is tangent to a central meridian. Deformation are more important as we are going futher from the central meridian. The Transverse Mercator projection is appropriate for region wich have a greater extent north-south than east-west.

The elliptical equations used here are series approximations, and their accuracy decreases as points move farther from the central meridian of the projection. The forward equations here are accurate to a less than a mm ±10 degrees from the central meridian, a few mm ±15 degrees from the central meridian and a few cm ±20 degrees from the central meridian. The spherical equations are not approximations and should always give the correct values.

There are a number of versions of the transverse mercator projection including the Universal (UTM) and Modified (MTM) Transverses Mercator projections. In these cases the earth is divided into zones. For the UTM the zones are 6 degrees wide, numbered from 1 to 60 proceeding east from 180 degrees longitude, and between lats 84 degrees North and 80 degrees South. The central meridian is taken as the center of the zone and the latitude of origin is the equator. A scale factor of 0.9996 and false easting of 500000m is used for all zones and a false northing of 10000000m is used for zones in the southern hemisphere.

NOTE: formulas used below are not those of Snyder, but rather those from the proj4 package of the USGS survey, which have been reproduced verbatim. USGS work is acknowledged here.

References:

• Proj-4.4.6 available at www.remotesensing.org/proj
  Relevent files are: PJ_tmerc.c, pj_mlfn.c, pj_fwd.c and pj_inv.c
• John P. Snyder (Map Projections - A Working Manual, U.S. Geological Survey Professional Paper 1395, 1987)
• "Coordinate Conversions and Transformations including Formulas", EPSG Guidence Note Number 7, Version 19.

Since:

2.1

See Also:

Transverse Mercator projection on MathWorld, "Transverse_Mercator" on Remote Sensing

Nested Class Summary

Nested Classes

Modifier and Type	Class and Description
static class	IdrTransverseMercator.Provider The org.geotools.referencing.operation.MathTransformProvider for a IdrTransverseMercator projection.
static class	IdrTransverseMercator.Provider_SouthOrientated The org.geotools.referencing.operation.MathTransformProvider for a South Orientated IdrTransverseMercator projection (EPSG code 9808).
static class	IdrTransverseMercator.Provider_TransverseMercatorZonedGridSystem

Constructor Summary

Constructors

Modifier	Constructor and Description
protected	IdrTransverseMercator(ParameterValueGroup parameters) Constructs a new map projection from the supplied parameters.

Method Summary

Methods

Modifier and Type	Method and Description
boolean	equals(Object object) Compares the specified object with this map projection for equality.
double	getCentralMeridian() Convenience method returning the meridian in the middle of current zone.
ParameterDescriptorGroup	getParameterDescriptors()
protected double	getToleranceForAssertions(double longitude, double latitude)
int	getZone() Convenience method computing the zone code from the central meridian.
int	hashCode() Returns a hash value for this projection.
protected Point2D	inverseTransformNormalized(double x, double y, Point2D ptDst) Transforms the specified (x,y) coordinate and stores the result in ptDst.
protected Point2D	transformNormalized(double x, double y, Point2D ptDst) Transforms the specified (x,y) coordinate (units in radians) and stores the result in ptDst (linear distance on a unit sphere).

Methods inherited from class java.lang.Object

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

Constructor Detail

IdrTransverseMercator

protected IdrTransverseMercator(ParameterValueGroup parameters)
                         throws ParameterNotFoundException

Constructs a new map projection from the supplied parameters.

Parameters:

parameters - The parameter values in standard units.

Throws:

ParameterNotFoundException - if a mandatory parameter is missing.

Method Detail

getParameterDescriptors

public ParameterDescriptorGroup getParameterDescriptors()

transformNormalized

protected Point2D transformNormalized(double x,
                          double y,
                          Point2D ptDst)
                               throws ProjectionException

Transforms the specified (x,y) coordinate (units in radians) and stores the result in ptDst (linear distance on a unit sphere).

Throws:

ProjectionException

inverseTransformNormalized

protected Point2D inverseTransformNormalized(double x,
                                 double y,
                                 Point2D ptDst)
                                      throws ProjectionException

Transforms the specified (x,y) coordinate and stores the result in ptDst.

Throws:

ProjectionException

getToleranceForAssertions

protected double getToleranceForAssertions(double longitude,
                               double latitude)

getZone

public int getZone()

Convenience method computing the zone code from the central meridian.

Returns:

The zone number, using the scalefactor and false easting to decide if this is a UTM or MTM case. Returns 0 if the case of the projection cannot be determined.

getCentralMeridian

public double getCentralMeridian()

Convenience method returning the meridian in the middle of current zone. This meridian is typically the central meridian. This method may be invoked to make sure that the central meridian is correctly set.

Returns:

The central meridian, using the scalefactor and false easting to decide if this is a UTM or MTM case. Returns Double.NaN if the case of the projection cannot be determined.

hashCode

public int hashCode()

Returns a hash value for this projection.

equals

public boolean equals(Object object)

Compares the specified object with this map projection for equality.