GeographicLib: GeographicLib::GeoCoords Class Reference

GeographicLib 2.7

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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 | EquatorialRadius () 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

- latitude and longitude
- UTM or UPS coordinates
- a string representation of these or an MGRS coordinate string

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>
#include <GeographicLib/GeoCoords.hpp>
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;
}
}
main
int main(int argc, const char *const argv[])
Definition Cart3Convert.cpp:52
GeoCoords.hpp
Header for GeographicLib::GeoCoords class.
GeographicLib::GeoCoords::GeoCoords
GeoCoords()
Definition GeoCoords.hpp:77
GeographicLib
Namespace for GeographicLib.
Definition Accumulator.cpp:12
std
Definition NearestNeighbor.hpp:806

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] | s | 1-element, 2-element, or 3-element string representation of the position.
  [in] | centerp | governs the interpretation of MGRS coordinates (see below).
  [in] | longfirst | governs the interpretation of geographic coordinates (see below).

Exceptions

  GeographicErr | if 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.

References Reset().

## ◆ 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] | zone | if specified, force the UTM/UPS representation to use a specified zone using the rules given in UTMUPS::zonespec.

Exceptions

  GeographicErr | if latitude is not in [−90°, 90°].
  GeographicErr | if zone cannot be used for this location.

Definition at line 194 of file GeoCoords.hpp.

References Reset(), and GeographicLib::UTMUPS::STANDARD.

## ◆ GeoCoords() [4/4]

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

Construct from UTM/UPS coordinates.

Parameters

  [in] | zone | UTM zone (zero means UPS).
  [in] | northp | hemisphere (true means north, false means south).
  [in] | easting | (meters).
  [in] | northing | (meters).

Exceptions

  GeographicErr | if zone, easting, or northing is outside its allowed range.

Definition at line 208 of file GeoCoords.hpp.

References Reset().

## 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] | s | 1-element, 2-element, or 3-element string representation of the position.
  [in] | centerp | governs the interpretation of MGRS coordinates.
  [in] | longfirst | governs the interpretation of geographic coordinates.

Exceptions

  GeographicErr | if the s is malformed.

Definition at line 19 of file GeoCoords.cpp.

References GeographicLib::DMS::DecodeLatLon(), GeographicLib::UTMUPS::DecodeZone(), GeographicLib::UTMUPS::Forward(), GeographicLib::MGRS::Reverse(), GeographicLib::UTMUPS::Reverse(), and GeographicLib::Utility::val().

Referenced by GeoCoords(), GeoCoords(), GeoCoords(), and 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] | zone | if specified, force the UTM/UPS representation to use a specified zone using the rules given in UTMUPS::zonespec.

Exceptions

  GeographicErr | if latitude is not in [−90°, 90°].
  GeographicErr | if zone cannot be used for this location.

Definition at line 238 of file GeoCoords.hpp.

References GeographicLib::Math::AngNormalize(), GeographicLib::UTMUPS::Forward(), and GeographicLib::UTMUPS::STANDARD.

## ◆ 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] | zone | UTM zone (zero means UPS).
  [in] | northp | hemisphere (true means north, false means south).
  [in] | easting | (meters).
  [in] | northing | (meters).

Exceptions

  GeographicErr | if zone, easting, or northing is outside its allowed range.

Definition at line 258 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::Reverse().

## ◆ Latitude()

Math::real GeographicLib::GeoCoords::Latitude | ( |  | ) | const
| inline

Returns
  latitude (degrees)

Definition at line 276 of file GeoCoords.hpp.

Referenced by main().

## ◆ Longitude()

Math::real GeographicLib::GeoCoords::Longitude | ( |  | ) | const
| inline

Returns
  longitude (degrees)

Definition at line 281 of file GeoCoords.hpp.

Referenced by main().

## ◆ Easting()

Math::real GeographicLib::GeoCoords::Easting | ( |  | ) | const
| inline

Returns
  easting (meters)

Definition at line 286 of file GeoCoords.hpp.

## ◆ Northing()

Math::real GeographicLib::GeoCoords::Northing | ( |  | ) | const
| inline

Returns
  northing (meters)

Definition at line 291 of file GeoCoords.hpp.

## ◆ Convergence()

Math::real GeographicLib::GeoCoords::Convergence | ( |  | ) | const
| inline

Returns
  meridian convergence (degrees) for the UTM/UPS projection.

Definition at line 296 of file GeoCoords.hpp.

## ◆ Scale()

Math::real GeographicLib::GeoCoords::Scale | ( |  | ) | const
| inline

Returns
  scale for the UTM/UPS projection.

Definition at line 301 of file GeoCoords.hpp.

## ◆ Northp()

bool GeographicLib::GeoCoords::Northp | ( |  | ) | const
| inline

Returns
  hemisphere (false means south, true means north).

Definition at line 306 of file GeoCoords.hpp.

Referenced by main().

## ◆ Hemisphere()

char GeographicLib::GeoCoords::Hemisphere | ( |  | ) | const
| inline

Returns
  hemisphere letter n or s.

Definition at line 311 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 316 of file GeoCoords.hpp.

## ◆ SetAltZone()

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

Specify alternate zone number.

Parameters

  [in] | zone | zone number for the alternate representation.

Exceptions

  GeographicErr | if 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 335 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::Forward(), GeographicLib::UTMUPS::MATCH, GeographicLib::UTMUPS::STANDARD, 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 353 of file GeoCoords.hpp.

Referenced by main().

## ◆ AltEasting()

Math::real GeographicLib::GeoCoords::AltEasting | ( |  | ) | const
| inline

Returns
  easting (meters) for alternate zone.

Definition at line 358 of file GeoCoords.hpp.

## ◆ AltNorthing()

Math::real GeographicLib::GeoCoords::AltNorthing | ( |  | ) | const
| inline

Returns
  northing (meters) for alternate zone.

Definition at line 363 of file GeoCoords.hpp.

## ◆ AltConvergence()

Math::real GeographicLib::GeoCoords::AltConvergence | ( |  | ) | const
| inline

Returns
  meridian convergence (degrees) for alternate zone.

Definition at line 368 of file GeoCoords.hpp.

Referenced by main().

## ◆ AltScale()

Math::real GeographicLib::GeoCoords::AltScale | ( |  | ) | const
| inline

Returns
  scale for alternate zone.

Definition at line 373 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] | prec | precision (relative to about 1m).
  [in] | longfirst | if true give longitude first (default = false)

Exceptions

  std::bad_alloc | if 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 61 of file GeoCoords.cpp.

References GeographicLib::Math::extra_digits(), and GeographicLib::Utility::str().

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] | prec | precision (relative to about 1m)
  [in] | longfirst | if true give longitude first (default = false)
  [in] | dmssep | if non-null, use as the DMS separator character (instead of d, ', " delimiters).

Exceptions

  std::bad_alloc | if 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 67 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] | prec | precision (relative to about 1m).

Exceptions

  std::bad_alloc | if 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 76 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] | prec | precision (relative to about 1m)
  [in] | abbrev | if true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)

Exceptions

  std::bad_alloc | if 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 116 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] | northp | hemisphere override
  [in] | prec | precision (relative to about 1m)
  [in] | abbrev | if true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)

Exceptions

  GeographicErr | if the hemisphere override attempts to change UPS N to UPS S or vice versa.
  std::bad_alloc | if memory for the string can't be allocated.

Returns
  UTM/UPS string representation: zone designator, easting, and northing.

Definition at line 122 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] | prec | precision (relative to about 1m).

Exceptions

  std::bad_alloc | if memory for the string can't be allocated.

Returns
  MGRS string.

Definition at line 84 of file GeoCoords.cpp.

References GeographicLib::MGRS::Forward().

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] | prec | precision (relative to about 1m)
  [in] | abbrev | if true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)

Exceptions

  std::bad_alloc | if memory for the string can't be allocated.

Returns
  UTM/UPS string representation: zone designator, easting, and northing.

Definition at line 133 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] | northp | hemisphere override
  [in] | prec | precision (relative to about 1m)
  [in] | abbrev | if true (the default) use abbreviated (n/s) notation for hemisphere; otherwise spell out the hemisphere (north/south)

Exceptions

  GeographicErr | if the hemisphere override attempts to change UPS n to UPS s or vice verse.
  std::bad_alloc | if memory for the string can't be allocated.

Returns
  UTM/UPS string representation: zone designator, easting, and northing.

Definition at line 140 of file GeoCoords.cpp.

References GeographicLib::UTMUPS::Transfer().

## ◆ EquatorialRadius()

Math::real GeographicLib::GeoCoords::EquatorialRadius | ( |  | ) | 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 530 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::EquatorialRadius().

## ◆ 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 538 of file GeoCoords.hpp.

References GeographicLib::UTMUPS::Flattening().

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

- GeoCoords.hpp
- GeoCoords.cpp