llh_converter

(Updated 2022/03/24)

This repository has two class implementation.

• HeightConverter
• LLHConverter

---

HeightConverter

Convert height between ellipsoid and orthometric library

Supported Geoid Models

• EGM2008-1
• GSIGEO2011 Ver2.1

Usage

llh_converter::HeightConverter hc;

hc.setGeoidType(height_converter::GeoidType::GSIGEO2011); // Select Geoid Model
// hc.setGeoidType(height_converter::GeoidType::EGM2008);

hc.setGSIGEOGeoidFile(path_to_gsigeo_asc_file);   // Load geoid data file when you select GSIGEO
// hc.setGSIGEOGeoidFile();  // If called with void, it try to read /usr/share/GSIGEO/gsigeo2011_ver2_1.asc

double geoid_heith = hc.getGeoid(lat, lon);   // Get geoid heigth with latitude/longitude in decimal degree

// Convert height between ellipsoid and orthometric
double converted_height = hc.convertHeight(lat, lon, h, height_converter::ConvertType::ORTHO2ELLIPS);
double converted_height = hc.convertHeight(lat, lon, h, height_converter::ConvertType::ELLIPS2ORTHO);

---

LLHConverter

Convert latitude/longitude/altitude into XYZ coordinate system.

Supported coordinate systems

• Millitary Grid Reference System (MGRS)
• Japan Plane Rectangular Coordinate System (JPRCS)

Usage

llh_converter::LLHConverter lc;
llh_converter::LLHParam param;  // parameter for conversion
param.use_mgrs = true;          // set true if you want to use MGRS
param.plane_num = 9;            // set the plane number when you use JPRCS
param.mgrs_code = "53SPU";      // MGRS grid code is required when you revert MGRS x/y into lat/lon
param.height_convert_type = llh_converter::ConvertType::ELLIPS2ORTHO;
                                // You can also convert height
param.geoid_type = llh_converter::GeoidType::EGM2008;
                                // Set geoid model

double lat_deg, lon_deg, alt;
double lat_rad = lat_deg * M_PI / 180.;
double lon_rad = lon_deg * M_PI / 180.;
double x, y, z;

lc.convertDeg2XYZ(lat_deg, lon_deg, alt, x, y, z, param);
lc.convertRad2XYZ(lat_rad, lon_rad, alt, x, y, z, param);

lc.revertXYZ2Deg(x, y, lat_deg, lon_deg, param);
lc.revertXYZ2Rad(x, y, lat_rad, lon_rad, param);

---

meridian convergence angle correction

The meridian convergence angle is the angle of difference between true north and coordinate north.

The meridian convergence angle is calculated by the getMeridianConvergence() function.

Usage

  llh_converter::LLHConverter lc;
  llh_converter::LLHParam param;
  param.use_mgrs = false;
  param.plane_num = 7;
  param.height_convert_type = llh_converter::ConvertType::NONE;
  param.geoid_type = llh_converter::GeoidType::EGM2008;

  llh_converter::LLA lla;
  llh_converter::XYZ xyz;
  lla.latitude = test_lat;
  lla.longitude = test_lon;
  lla.altitude = 30.0;
  llh_converter.convertDeg2XYZ(lla.latitude, lla.longitude, lla.altitude, xyz.x, xyz.y, xyz.z, param);
  double mca = llh_converter::getMeridianConvergence(lla, xyz, llh_converter, param); // meridian convergence angle

Install

sudo apt update
sudo apt install libgeographic-dev geographiclib-tools geographiclib-doc

sudo geographiclib-get-geoids best

mkdir -p test_ws/src
cd test_ws/src/
git clone https://github.com/MapIV/height_converter.git
sudo mkdir /usr/share/GSIGEO
sudo cp llh_converter/data/gsigeo2011_ver2_1.asc /usr/share/GSIGEO/
cd ../../
catkin_make -DCMAKE_BUILD_TYPE=Release

Geoid model data

This package contains GSIGEO2011 geoid data file which is provided by Geospatial Information Authority of Japan.

Official Website of Geospatial Information Authority of Japan

LICENSE

This package is provided under the BSD 3-Clauses License.