// Copyright (c) 2022, ETH Zurich and UNC Chapel Hill.
// All rights reserved.
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// Author: Johannes L. Schoenberger (jsch-at-demuc-dot-de)

#ifndef COLMAP_SRC_BASE_GPS_H_
#define COLMAP_SRC_BASE_GPS_H_

#include <vector>

#include <Eigen/Core>

#include "util/alignment.h"
#include "util/types.h"

namespace colmap {

// Transform ellipsoidal GPS coordinates to Cartesian GPS coordinate
// representation and vice versa.
class GPSTransform {
 public:
  enum ELLIPSOID { GRS80, WGS84 };

  explicit GPSTransform(const int ellipsoid = GRS80);

  std::vector<Eigen::Vector3d> EllToXYZ(
      const std::vector<Eigen::Vector3d>& ell) const;

  std::vector<Eigen::Vector3d> XYZToEll(
      const std::vector<Eigen::Vector3d>& xyz) const;

  // Convert GPS (lat / lon / alt) to ENU coords. with lat0 and lon0
  // defining the origin of the ENU frame
  std::vector<Eigen::Vector3d> EllToENU(const std::vector<Eigen::Vector3d>& ell,
                                        const double lat0,
                                        const double lon0) const;

  std::vector<Eigen::Vector3d> XYZToENU(const std::vector<Eigen::Vector3d>& xyz,
                                        const double lat0,
                                        const double lon0) const;

  std::vector<Eigen::Vector3d> ENUToEll(const std::vector<Eigen::Vector3d>& enu,
                                        const double lat0, const double lon0,
                                        const double alt0) const;

  std::vector<Eigen::Vector3d> ENUToXYZ(const std::vector<Eigen::Vector3d>& enu,
                                        const double lat0, const double lon0,
                                        const double alt0) const;

 private:
  // Semimajor axis.
  double a_;
  // Semiminor axis.
  double b_;
  // Flattening.
  double f_;
  // Numerical eccentricity.
  double e2_;
};

}  // namespace colmap

#endif  // COLMAP_SRC_BASE_GPS_H_