GeographicLib  1.49
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GeographicLib::GeoCoords Class Reference

Conversion between geographic coordinates. More...

#include <GeographicLib/GeoCoords.hpp>

Public Member Functions

Initializing the GeoCoords object
 GeoCoords ()
 
 GeoCoords (const std::string &s, bool centerp=true, bool longfirst=false)
 
 GeoCoords (real latitude, real longitude, int zone=UTMUPS::STANDARD)
 
 GeoCoords (int zone, bool northp, real easting, real northing)
 
void Reset (const std::string &s, bool centerp=true, bool longfirst=false)
 
void Reset (real latitude, real longitude, int zone=UTMUPS::STANDARD)
 
void Reset (int zone, bool northp, real easting, real northing)
 
Querying the GeoCoords object
Math::real Latitude () const
 
Math::real Longitude () const
 
Math::real Easting () const
 
Math::real Northing () const
 
Math::real Convergence () const
 
Math::real Scale () const
 
bool Northp () const
 
char Hemisphere () const
 
int Zone () const
 
Setting and querying the alternate zone
void SetAltZone (int zone=UTMUPS::STANDARD) const
 
int AltZone () const
 
Math::real AltEasting () const
 
Math::real AltNorthing () const
 
Math::real AltConvergence () const
 
Math::real AltScale () const
 
String representations of the GeoCoords object
std::string GeoRepresentation (int prec=0, bool longfirst=false) const
 
std::string DMSRepresentation (int prec=0, bool longfirst=false, char dmssep=char(0)) const
 
std::string MGRSRepresentation (int prec=0) const
 
std::string UTMUPSRepresentation (int prec=0, bool abbrev=true) const
 
std::string UTMUPSRepresentation (bool northp, int prec=0, bool abbrev=true) const
 
std::string AltMGRSRepresentation (int prec=0) const
 
std::string AltUTMUPSRepresentation (int prec=0, bool abbrev=true) const
 
std::string AltUTMUPSRepresentation (bool northp, int prec=0, bool abbrev=true) const
 
Inspector functions
Math::real MajorRadius () const
 
Math::real Flattening () const
 

Detailed Description

Conversion between geographic coordinates.

This class stores a geographic position which may be set via the constructors or Reset via

The state consists of the latitude and longitude and the supplied UTM or UPS coordinates (possibly derived from the MGRS coordinates). If latitude and longitude were given then the UTM/UPS coordinates follows the standard conventions.

The mutable state consists of the UTM or UPS coordinates for a alternate zone. A method SetAltZone is provided to set the alternate UPS/UTM zone.

Methods are provided to return the geographic coordinates, the input UTM or UPS coordinates (and associated meridian convergence and scale), or alternate UTM or UPS coordinates (and their associated meridian convergence and scale).

Once the input string has been parsed, you can print the result out in any of the formats, decimal degrees, degrees minutes seconds, MGRS, UTM/UPS.

Example of use:

// Example of using the GeographicLib::GeoCoords class
#include <iostream>
#include <exception>
using namespace std;
using namespace GeographicLib;
int main() {
try {
// Miscellaneous conversions
double lat = 33.3, lon = 44.4;
GeoCoords c(lat, lon);
cout << c.MGRSRepresentation(-3) << "\n";
c.Reset("18TWN0050");
cout << c.DMSRepresentation() << "\n";
cout << c.Latitude() << " " << c.Longitude() << "\n";
c.Reset("1d38'W 55d30'N");
cout << c.GeoRepresentation() << "\n";
}
catch (const exception& e) {
cerr << "Caught exception: " << e.what() << "\n";
return 1;
}
}

GeoConvert is a command-line utility providing access to the functionality of GeoCoords.

Definition at line 49 of file GeoCoords.hpp.

Constructor & Destructor Documentation

◆ GeoCoords() [1/4]

GeographicLib::GeoCoords::GeoCoords ( )
inline

The default constructor sets the coordinate as undefined.

Definition at line 77 of file GeoCoords.hpp.

◆ GeoCoords() [2/4]

GeographicLib::GeoCoords::GeoCoords ( const std::string &  s,
bool  centerp = true,
bool  longfirst = false 
)
inlineexplicit

Construct from a string.

Parameters
[in]s1-element, 2-element, or 3-element string representation of the position.
[in]centerpgoverns the interpretation of MGRS coordinates (see below).
[in]longfirstgoverns the interpretation of geographic coordinates (see below).
Exceptions
GeographicErrif the s is malformed (see below).

Parse as a string and interpret it as a geographic position. The input string is broken into space (or comma) separated pieces and Basic decision on which format is based on number of components

  1. MGRS
  2. "Lat Long" or "Long Lat"
  3. "Zone Easting Northing" or "Easting Northing Zone"

The following inputs are approximately the same (Ar Ramadi Bridge, Iraq)

  • Latitude and Longitude
    • 33.44 43.27
    • N33d26.4' E43d16.2'
    • 43d16'12"E 33d26'24"N
    • 43:16:12E 33:26:24
  • MGRS
    • 38SLC30
    • 38SLC391014
    • 38SLC3918701405
    • 37SHT9708
  • UTM
    • 38n 339188 3701405
    • 897039 3708229 37n

Latitude and Longitude parsing: Latitude precedes longitude, unless a N, S, E, W hemisphere designator is used on one or both coordinates. If longfirst = true (default is false), then longitude precedes latitude in the absence of a hemisphere designator. Thus (with longfirst = false)

  • 40 -75
  • N40 W75
  • -75 N40
  • 75W 40N
  • E-75 -40S

are all the same position. The coordinates may be given in decimal degrees, degrees and decimal minutes, degrees, minutes, seconds, etc. Use d, ', and " to mark off the degrees, minutes and seconds. Various alternative symbols for degrees, minutes, and seconds are allowed. Alternatively, use : to separate these components. A single addition or subtraction is allowed. (See DMS::Decode for details.) Thus

  • 40d30'30"
  • 40d30'30
  • 40°30'30
  • 40d30.5'
  • 40d30.5
  • 40:30:30
  • 40:30.5
  • 40.508333333
  • 40:30+0:0:30
  • 40:31-0:0.5

all specify the same angle. The leading sign applies to the following components so -1d30 is -(1+30/60) = −1.5. However, note that -1:30-0:0:15 is parsed as (-1:30) + (-0:0:15) = −(1+30/60) − (15/3600). Latitudes must be in the range [−90°, 90°]. Internally longitudes are reduced to the range [−180°, 180°].

UTM/UPS parsing: For UTM zones (−80° ≤ Lat < 84°), the zone designator is made up of a zone number (for 1 to 60) and a hemisphere letter (n or s), e.g., 38n (38north can also be used). The latitude band designer ([C–M] in the southern hemisphere and [N–X] in the northern) should NOT be used. (This is part of the MGRS coordinate.) The zone designator for the poles (where UPS is employed) is a hemisphere letter by itself, i.e., n or s (north or south can also be used).

MGRS parsing interprets the grid references as square area at the specified precision (1m, 10m, 100m, etc.). If centerp = true (the default), the center of this square is then taken to be the precise position; thus:

  • 38SMB = 38n 450000 3650000
  • 38SMB4484 = 38n 444500 3684500
  • 38SMB44148470 = 38n 444145 3684705

Otherwise, the "south-west" corner of the square is used, i.e.,

  • 38SMB = 38n 400000 3600000
  • 38SMB4484 = 38n 444000 3684000
  • 38SMB44148470 = 38n 444140 3684700

Definition at line 179 of file GeoCoords.hpp.

◆ GeoCoords() [3/4]

GeographicLib::GeoCoords::GeoCoords ( real  latitude,
real  longitude,
int  zone = UTMUPS::STANDARD 
)
inline

Construct from geographic coordinates.

Parameters
[in]latitude(degrees).
[in]longitude(degrees).
[in]zoneif specified, force the UTM/UPS representation to use a specified zone using the rules given in UTMUPS::zonespec.
Exceptions
GeographicErrif latitude is not in [−90°, 90°].
GeographicErrif zone cannot be used for this location.

Definition at line 194 of file GeoCoords.hpp.

◆ GeoCoords() [4/4]

GeographicLib::GeoCoords::GeoCoords ( int  zone,
bool  northp,
real  easting,
real  northing 
)
inline

Construct from UTM/UPS coordinates.

Parameters
[in]zoneUTM zone (zero means UPS).
[in]northphemisphere (true means north, false means south).
[in]easting(meters).
[in]northing(meters).
Exceptions
GeographicErrif zone, easting, or northing is outside its allowed range.

Definition at line 208 of file GeoCoords.hpp.

Member Function Documentation

◆ Reset() [1/3]

void GeographicLib::GeoCoords::Reset ( const std::string &  s,
bool  centerp = true,
bool  longfirst = false 
)

Reset the location from a string. See GeoCoords(const std::string& s, bool centerp, bool longfirst).

Parameters
[in]s1-element, 2-element, or 3-element string representation of the position.
[in]centerpgoverns the interpretation of MGRS coordinates.
[in]longfirstgoverns the interpretation of geographic coordinates.
Exceptions
GeographicErrif the s is malformed.

Definition at line 19 of file GeoCoords.cpp.

References GeographicLib::Math::AngNormalize(), GeographicLib::DMS::DecodeLatLon(), GeographicLib::UTMUPS::DecodeZone(), GeographicLib::UTMUPS::Forward(), GeographicLib::UTMUPS::Reverse(), and GeographicLib::MGRS::Reverse().

Referenced by main().

◆ Reset() [2/3]

void GeographicLib::GeoCoords::Reset ( real  latitude,
real  longitude,
int  zone = UTMUPS::STANDARD 
)
inline

Reset the location in terms of geographic coordinates. See GeoCoords(real latitude, real longitude, int zone).

Parameters
[in]latitude(degrees).
[in]longitude(degrees).
[in]zoneif specified, force the UTM/UPS representation to use a specified zone using the rules given in UTMUPS::zonespec.
Exceptions
GeographicErrif latitude is not in [−90°, 90°].
GeographicErrif zone cannot be used for this location.

Definition at line 238 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::Forward().

◆ Reset() [3/3]

void GeographicLib::GeoCoords::Reset ( int  zone,
bool  northp,
real  easting,
real  northing 
)
inline

Reset the location in terms of UPS/UPS coordinates. See GeoCoords(int zone, bool northp, real easting, real northing).

Parameters
[in]zoneUTM zone (zero means UPS).
[in]northphemisphere (true means north, false means south).
[in]easting(meters).
[in]northing(meters).
Exceptions
GeographicErrif zone, easting, or northing is outside its allowed range.

Definition at line 260 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::Reverse().

◆ Latitude()

Math::real GeographicLib::GeoCoords::Latitude ( ) const
inline
Returns
latitude (degrees)

Definition at line 278 of file GeoCoords.hpp.

Referenced by main().

◆ Longitude()

Math::real GeographicLib::GeoCoords::Longitude ( ) const
inline
Returns
longitude (degrees)

Definition at line 283 of file GeoCoords.hpp.

Referenced by main().

◆ Easting()

Math::real GeographicLib::GeoCoords::Easting ( ) const
inline
Returns
easting (meters)

Definition at line 288 of file GeoCoords.hpp.

◆ Northing()

Math::real GeographicLib::GeoCoords::Northing ( ) const
inline
Returns
northing (meters)

Definition at line 293 of file GeoCoords.hpp.

◆ Convergence()

Math::real GeographicLib::GeoCoords::Convergence ( ) const
inline
Returns
meridian convergence (degrees) for the UTM/UPS projection.

Definition at line 298 of file GeoCoords.hpp.

◆ Scale()

Math::real GeographicLib::GeoCoords::Scale ( ) const
inline
Returns
scale for the UTM/UPS projection.

Definition at line 303 of file GeoCoords.hpp.

◆ Northp()

bool GeographicLib::GeoCoords::Northp ( ) const
inline
Returns
hemisphere (false means south, true means north).

Definition at line 308 of file GeoCoords.hpp.

Referenced by main().

◆ Hemisphere()

char GeographicLib::GeoCoords::Hemisphere ( ) const
inline
Returns
hemisphere letter n or s.

Definition at line 313 of file GeoCoords.hpp.

◆ Zone()

int GeographicLib::GeoCoords::Zone ( ) const
inline
Returns
the zone corresponding to the input (return 0 for UPS).

Definition at line 318 of file GeoCoords.hpp.

◆ SetAltZone()

void GeographicLib::GeoCoords::SetAltZone ( int  zone = UTMUPS::STANDARD) const
inline

Specify alternate zone number.

Parameters
[in]zonezone number for the alternate representation.
Exceptions
GeographicErrif zone cannot be used for this location.

See UTMUPS::zonespec for more information on the interpretation of zone. Note that zone == UTMUPS::STANDARD (the default) use the standard UPS or UTM zone, UTMUPS::MATCH does nothing retaining the existing alternate representation. Before this is called the alternate zone is the input zone.

Definition at line 337 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::Forward(), GeographicLib::UTMUPS::MATCH, and GeographicLib::UTMUPS::StandardZone().

Referenced by main().

◆ AltZone()

int GeographicLib::GeoCoords::AltZone ( ) const
inline
Returns
current alternate zone (return 0 for UPS).

Definition at line 355 of file GeoCoords.hpp.

Referenced by main().

◆ AltEasting()

Math::real GeographicLib::GeoCoords::AltEasting ( ) const
inline
Returns
easting (meters) for alternate zone.

Definition at line 360 of file GeoCoords.hpp.

◆ AltNorthing()

Math::real GeographicLib::GeoCoords::AltNorthing ( ) const
inline
Returns
northing (meters) for alternate zone.

Definition at line 365 of file GeoCoords.hpp.

◆ AltConvergence()

Math::real GeographicLib::GeoCoords::AltConvergence ( ) const
inline
Returns
meridian convergence (degrees) for alternate zone.

Definition at line 370 of file GeoCoords.hpp.

Referenced by main().

◆ AltScale()

Math::real GeographicLib::GeoCoords::AltScale ( ) const
inline
Returns
scale for alternate zone.

Definition at line 375 of file GeoCoords.hpp.

Referenced by main().

◆ GeoRepresentation()

string GeographicLib::GeoCoords::GeoRepresentation ( int  prec = 0,
bool  longfirst = false 
) const

String representation with latitude and longitude as signed decimal degrees.

Parameters
[in]precprecision (relative to about 1m).
[in]longfirstif true give longitude first (default = false)
Exceptions
std::bad_allocif memory for the string can't be allocated.
Returns
decimal latitude/longitude string representation.

Precision specifies accuracy of representation as follows:

  • prec = −5 (min), 1°
  • prec = 0, 10−5° (about 1m)
  • prec = 3, 10−8°
  • prec = 9 (max), 10−14°

Definition at line 62 of file GeoCoords.cpp.

References GeographicLib::Math::extra_digits(), and GeographicLib::Math::isnan().

Referenced by main().

◆ DMSRepresentation()

string GeographicLib::GeoCoords::DMSRepresentation ( int  prec = 0,
bool  longfirst = false,
char  dmssep = char(0) 
) const

String representation with latitude and longitude as degrees, minutes, seconds, and hemisphere.

Parameters
[in]precprecision (relative to about 1m)
[in]longfirstif true give longitude first (default = false)
[in]dmssepif non-null, use as the DMS separator character (instead of d, ', " delimiters).
Exceptions
std::bad_allocif memory for the string can't be allocated.
Returns
DMS latitude/longitude string representation.

Precision specifies accuracy of representation as follows:

  • prec = −5 (min), 1°
  • prec = −4, 0.1°
  • prec = −3, 1'
  • prec = −2, 0.1'
  • prec = −1, 1"
  • prec = 0, 0.1" (about 3m)
  • prec = 1, 0.01"
  • prec = 10 (max), 10−11"

Definition at line 80 of file GeoCoords.cpp.

References GeographicLib::DMS::Encode(), GeographicLib::Math::extra_digits(), GeographicLib::DMS::LATITUDE, and GeographicLib::DMS::LONGITUDE.

Referenced by main().

◆ MGRSRepresentation()

string GeographicLib::GeoCoords::MGRSRepresentation ( int  prec = 0) const

MGRS string.

Parameters
[in]precprecision (relative to about 1m).
Exceptions
std::bad_allocif memory for the string can't be allocated.
Returns
MGRS string.

This gives the coordinates of the enclosing grid square with size given by the precision. Thus 38n 444180 3684790 converted to a MGRS coordinate at precision −2 (100m) is 38SMB441847 and not 38SMB442848. prec specifies the precision of the MGRS string as follows:

  • prec = −6 (min), only the grid zone is returned, e.g., 38S
  • prec = −5, 100km, e.g., 38SMB
  • prec = −4, 10km
  • prec = −3, 1km
  • prec = −2, 100m
  • prec = −1, 10m
  • prec = 0, 1m
  • prec = 1, 0.1m
  • prec = 6 (max), 1μm

Definition at line 89 of file GeoCoords.cpp.

References GeographicLib::MGRS::Forward().

◆ UTMUPSRepresentation() [1/2]

string GeographicLib::GeoCoords::UTMUPSRepresentation ( int  prec = 0,
bool  abbrev = true 
) const

UTM/UPS string.

Parameters
[in]precprecision (relative to about 1m)
[in]abbrevif true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)
Exceptions
std::bad_allocif memory for the string can't be allocated.
Returns
UTM/UPS string representation: zone designator, easting, and northing.

Precision specifies accuracy of representation as follows:

  • prec = −5 (min), 100km
  • prec = −3, 1km
  • prec = 0, 1m
  • prec = 3, 1mm
  • prec = 6, 1μm
  • prec = 9 (max), 1nm

Definition at line 129 of file GeoCoords.cpp.

◆ UTMUPSRepresentation() [2/2]

string GeographicLib::GeoCoords::UTMUPSRepresentation ( bool  northp,
int  prec = 0,
bool  abbrev = true 
) const

UTM/UPS string with hemisphere override.

Parameters
[in]northphemisphere override
[in]precprecision (relative to about 1m)
[in]abbrevif true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)
Exceptions
GeographicErrif the hemisphere override attempts to change UPS N to UPS S or vice versa.
std::bad_allocif memory for the string can't be allocated.
Returns
UTM/UPS string representation: zone designator, easting, and northing.

Definition at line 135 of file GeoCoords.cpp.

References GeographicLib::UTMUPS::Transfer().

◆ AltMGRSRepresentation()

string GeographicLib::GeoCoords::AltMGRSRepresentation ( int  prec = 0) const

MGRS string for the alternate zone. See GeoCoords::MGRSRepresentation.

Parameters
[in]precprecision (relative to about 1m).
Exceptions
std::bad_allocif memory for the string can't be allocated.
Returns
MGRS string.

Definition at line 97 of file GeoCoords.cpp.

References GeographicLib::UTMUPS::EncodeZone(), GeographicLib::Math::extra_digits(), GeographicLib::MGRS::Forward(), GeographicLib::Math::isfinite(), and GeographicLib::Utility::str().

Referenced by main().

◆ AltUTMUPSRepresentation() [1/2]

string GeographicLib::GeoCoords::AltUTMUPSRepresentation ( int  prec = 0,
bool  abbrev = true 
) const

UTM/UPS string for the alternate zone. See GeoCoords::UTMUPSRepresentation.

Parameters
[in]precprecision (relative to about 1m)
[in]abbrevif true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)
Exceptions
std::bad_allocif memory for the string can't be allocated.
Returns
UTM/UPS string representation: zone designator, easting, and northing.

Definition at line 146 of file GeoCoords.cpp.

Referenced by main().

◆ AltUTMUPSRepresentation() [2/2]

string GeographicLib::GeoCoords::AltUTMUPSRepresentation ( bool  northp,
int  prec = 0,
bool  abbrev = true 
) const

UTM/UPS string for the alternate zone, with hemisphere override.

Parameters
[in]northphemisphere override
[in]precprecision (relative to about 1m)
[in]abbrevif true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)
Exceptions
GeographicErrif the hemisphere override attempts to change UPS n to UPS s or vice verse.
std::bad_allocif memory for the string can't be allocated.
Returns
UTM/UPS string representation: zone designator, easting, and northing.

Definition at line 153 of file GeoCoords.cpp.

References GeographicLib::Math::isnan(), GeographicLib::UTMUPS::Transfer(), GeographicLib::UTMUPS::UPS, and GeographicLib::UTMUPS::UTMShift().

◆ MajorRadius()

Math::real GeographicLib::GeoCoords::MajorRadius ( ) const
inline
Returns
a the equatorial radius of the WGS84 ellipsoid (meters).

(The WGS84 value is returned because the UTM and UPS projections are based on this ellipsoid.)

Definition at line 532 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::MajorRadius().

◆ Flattening()

Math::real GeographicLib::GeoCoords::Flattening ( ) const
inline
Returns
f the flattening of the WGS84 ellipsoid.

(The WGS84 value is returned because the UTM and UPS projections are based on this ellipsoid.)

Definition at line 540 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::Flattening().


The documentation for this class was generated from the following files: