GeographicLib: GeographicLib::GeoCoords Class Reference (original) (raw)

Conversion between geographic coordinates. More...

#include <[GeographicLib/GeoCoords.hpp](GeoCoords%5F8hpp%5Fsource.html)>

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:

#include

#include

using namespace std;

try {

double lat = 33.3, lon = 44.4;

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;

}

}

int main(int argc, const char *const argv[])

Header for GeographicLib::GeoCoords class.

Conversion between geographic coordinates.

Namespace for GeographicLib.

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

Definition at line 49 of file GeoCoords.hpp.

The default constructor sets the coordinate as undefined.

Definition at line 77 of file GeoCoords.hpp.

◆ GeoCoords() [2/4]

Construct from a string.

Parameters

Exceptions

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]

Construct from geographic coordinates.

Parameters

Exceptions

Definition at line 194 of file GeoCoords.hpp.

◆ GeoCoords() [4/4]

Construct from UTM/UPS coordinates.

Parameters

Exceptions

Definition at line 208 of file GeoCoords.hpp.

◆ Reset() [1/3]

◆ Reset() [2/3]

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

Parameters

Exceptions

Definition at line 238 of file GeoCoords.hpp.

◆ Reset() [3/3]

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

Parameters

Exceptions

Definition at line 258 of file GeoCoords.hpp.

◆ Latitude()

◆ Longitude()

◆ Easting()

◆ Northing()

◆ Convergence()

Returns

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

Definition at line 296 of file GeoCoords.hpp.

◆ Scale()

Returns

scale for the UTM/UPS projection.

Definition at line 301 of file GeoCoords.hpp.

◆ Northp()

Returns

hemisphere (false means south, true means north).

Definition at line 306 of file GeoCoords.hpp.

Referenced by main().

◆ Hemisphere()

◆ Zone()

Returns

the zone corresponding to the input (return 0 for UPS).

Definition at line 316 of file GeoCoords.hpp.

◆ SetAltZone()

Specify alternate zone number.

Parameters

Exceptions

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.

Referenced by main().

◆ AltZone()

Returns

current alternate zone (return 0 for UPS).

Definition at line 353 of file GeoCoords.hpp.

Referenced by main().

◆ AltEasting()

Returns

easting (meters) for alternate zone.

Definition at line 358 of file GeoCoords.hpp.

◆ AltNorthing()

Returns

northing (meters) for alternate zone.

Definition at line 363 of file GeoCoords.hpp.

◆ AltConvergence()

Returns

meridian convergence (degrees) for alternate zone.

Definition at line 368 of file GeoCoords.hpp.

Referenced by main().

◆ AltScale()

◆ GeoRepresentation()

String representation with latitude and longitude as signed decimal degrees.

Parameters

Exceptions

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

Parameters

Exceptions

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 68 of file GeoCoords.cpp.

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

Referenced by main().

◆ MGRSRepresentation()

MGRS string.

Parameters

Exceptions

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 77 of file GeoCoords.cpp.

References GeographicLib::MGRS::Forward().

◆ UTMUPSRepresentation() [1/2]

UTM/UPS string.

Parameters

Exceptions

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 117 of file GeoCoords.cpp.

◆ UTMUPSRepresentation() [2/2]

UTM/UPS string with hemisphere override.

Parameters

Exceptions

Returns

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

Definition at line 123 of file GeoCoords.cpp.

References GeographicLib::UTMUPS::Transfer().

◆ AltMGRSRepresentation()

◆ AltUTMUPSRepresentation() [1/2]

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

Parameters

Exceptions

Returns

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

Definition at line 134 of file GeoCoords.cpp.

Referenced by main().

◆ AltUTMUPSRepresentation() [2/2]

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

Parameters

Exceptions

Returns

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

Definition at line 141 of file GeoCoords.cpp.

References GeographicLib::UTMUPS::Transfer().

◆ EquatorialRadius()

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.

◆ Flattening()

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.

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

• GeoCoords.hpp
• GeoCoords.cpp