Program Listing for File lola_dem.h

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#pragma once

#include <filesystem>
#include <string>
#include <vector>

#include "lupnt/core/definitions.h"

namespace lupnt {

  struct LolaSite {
    std::string id;
    std::string name;
    double lat_deg;
    double lon_deg;
  };

  const std::vector<LolaSite>& GetLolaSites();

  const LolaSite& SelectLolaSite(double lat_deg, double lon_deg);

  std::string LolaDemUrl(const std::string& site_id);

  std::filesystem::path DownloadLolaDem(const std::string& site_id);

  class LunarDem {
  public:
    LunarDem() = default;

    LunarDem(const MatXd& x, const MatXd& y, const MatXd& elev, const LolaSite& site);

    double GetElevation(double x, double y) const;

    double GetElevationLatLon(double lat_deg, double lon_deg) const;

    const MatXd& x() const { return x_; }
    const MatXd& y() const { return y_; }
    const MatXd& elevation() const { return elev_; }
    const LolaSite& site() const { return site_; }

    int rows() const { return static_cast<int>(elev_.rows()); }
    int cols() const { return static_cast<int>(elev_.cols()); }

    double x_min() const { return std::min(x_left_, x_right_); }
    double x_max() const { return std::max(x_left_, x_right_); }
    double y_min() const { return std::min(y_top_, y_bottom_); }
    double y_max() const { return std::max(y_top_, y_bottom_); }
    double center_x() const { return 0.5 * (x_left_ + x_right_); }
    double center_y() const { return 0.5 * (y_top_ + y_bottom_); }

  private:
    MatXd x_, y_, elev_;
    LolaSite site_;

    // Regular-grid parameters cached for fast bilinear lookup. Columns increase in x,
    // rows increase in y (dy_ is typically negative for a north-up raster).
    double x0_ = 0.0, y0_ = 0.0;  // coordinate of pixel-center (row 0, col 0)
    double dx_ = 1.0, dy_ = 1.0;  // per-column / per-row coordinate step [m]
    int nx_ = 0, ny_ = 0;
    double x_left_ = 0.0, x_right_ = 0.0, y_top_ = 0.0, y_bottom_ = 0.0;
  };

  LunarDem LoadLolaDem(double lat_deg, double lon_deg, double half_width_m = 5000.0,
                       double max_res = 20.0, const std::filesystem::path& dem_file = {});

}  // namespace lupnt