Added intersectSurface to NaifDskShape so the intercept point would b… (#4997)

- Fixed CNetCombinePt logging functionality such that only merged points are included in the log. [#4973](https://github.com/USGS-Astrogeology/ISIS3/issues/4973)

- Removed SpkCenterId functions in Cassini camera models due to spkwriter writing positions of Cassini relative to Titan but labeling

it in the kernel as the position relative to the Saturn Barycenter. [#4942](https://github.com/USGS-Astrogeology/ISIS3/issues/4942)

- Corrected issue where footprintinit would fail with a segmentation error. [4943](https://github.com/USGS-Astrogeology/ISIS3/issues/4943)

## [7.0.0] - 2022-02-11

    setName("DSK");

  }

  /**

   * @brief Constructor provided for instantiation from an ISIS cube

   *

  }

  /**

   * @brief Constructor for creating new shape model from the same DSK file

   *

    return ( success );

  }

  /**

  * @brief Compute surface intersection with optional occlusion check

  *

  * This method sets the surface point at the given latitude, longitude. The

  * derived model is called to get the radius at that location to complete the

  * accuracy of the surface point, them the derived method is called to complete

  * the intersection.

  *

  * @author 2022-07-14 Stuart Sides, Jesse Mapel

  *

  * @param surfpt       Absolute point on the surface to check

  * @param observerPos  Position of the observer

  * @param backCheck    Flag to indicate occlusion check

  *

  * @return bool        True if the intersection point is valid (visable)

  */

  bool NaifDskShape::intersectSurface(const SurfacePoint &surfpt,

                                    const std::vector<double> &observerPos,

                                    const bool &backCheck) {

    std::vector<double> look(3);

    look[0] = surfpt.GetX().kilometers() - observerPos[0];

    look[1] = surfpt.GetY().kilometers() - observerPos[1];

    look[2] = surfpt.GetZ().kilometers() - observerPos[2];

    return intersectSurface(observerPos, look);

  }

  /**

   * @brief Determine DEM radius at a given lat/lon grid point

   *

    return (Distance());

  }

  /**

   * @brief Set the normal vector to the intercept point normal

   *

   * @param neighborPoints Input body-fixed points to compute normal for

   */

  void NaifDskShape::calculateLocalNormal(QVector<double *> neighborPoints) {

    // Sanity check

    if ( !hasIntersection() ) { // hasIntersection()  <==>  !m_intercept.isNull()

      QString mess = "Intercept point does not exist - cannot provide normal vector";

     calculateSurfaceNormal();

  }

  /** Return the surface normal of the ellipsi=oud */

  void NaifDskShape::calculateSurfaceNormal() {

    // ShapeModel (parent class) throws error if no intersection

    return;

  }

  /**

   * @brief Compute the true surface normal vector of an ellipsoid

   *

    return (norm);

  }

  /** Returns a direct reference to the DSK plate model file interface */

  const NaifDskPlateModel &NaifDskShape::model() const {

    return (m_model);

  }

  /**

   * @brief Returns a pointer to the current intercept

   *

      bool intersectSurface(std::vector<double> observerPos,

                            std::vector<double> lookDirection);

      bool intersectSurface(const SurfacePoint &surfpt,

                            const std::vector<double> &observerPos,

                            const bool &backCheck=true);

      // Calculate the default normal of the current intersection point

      void calculateDefaultNormal();

      const NaifDskPlateModel &model() const;

      const Intercept *intercept() const;

    private:

      // Disallow copying because ShapeModel is not copyable

      NaifDskShape(const NaifDskShape &model);

Construct NaifDskShape object from cube labels with ShapeModel=DSK file.

Try to intersect surface at obsPos (0,0,1000) and lookDir (0,-1,-1)

Intersection successful?      "No"

Try to intersect surface at obsPos (1000,0,0) and lookDir (-1,0,0)

Intercept X =  0.28911

Intercept Y =  0

Intercept Z =  0

Intersection successful?      "Yes"

Construct NaifDskShape object from cube labels with ElevationModel=DSK file.

Try to intersect surface at obsPos (1000,0,0) and lookDir (-1,0,0)

**USER ERROR** NAIF DSK file [Null] does not exist.

Thrown by setLocalNormalFromIntercept() - Failed to find intercept. 

**PROGRAMMER ERROR** Intercept point does not exist - cannot provide normal vector.

Thrown by calculateLocalNormal() - Failed to find intercept for normal vector. 

**PROGRAMMER ERROR** Intercept point does not exist - cannot provide normal vector.

#include "Angle.h"

#include "Cube.h"

#include "Displacement.h"

#include "Distance.h"

#include "FileName.h"

#include "IException.h"

    success = shapeModelFromPvlShape.intersectSurface(obsPos, lookDir);

    qDebug() << "Intersection successful?     " << toString(success);

    qDebug() << "Try to intersect surface at obsPos (1000,0,0) and ground point (1,0,0)";

    Displacement x(1.0, Displacement::Meters);

    Displacement y(0.0, Displacement::Meters);

    Displacement z(0.0, Displacement::Meters);

    SurfacePoint SurfPt(x, y, z);

    obsPos[0]  = 1000.0;  obsPos[1]  = 0.0;   obsPos[2]  = 0.0;

    success = shapeModelFromPvlShape.intersectSurface(SurfPt, obsPos);

    if (success) {

      SurfacePoint *point = shapeModelFromPvlShape.surfaceIntersection();

      qDebug() << "Intercept X = " << point->DisplacementToDouble(point->GetX(), SurfacePoint::Kilometers);

      qDebug() << "Intercept Y = " << point->DisplacementToDouble(point->GetY(), SurfacePoint::Kilometers);

      qDebug() << "Intercept Z = " << point->DisplacementToDouble(point->GetZ(), SurfacePoint::Kilometers);

    }

    qDebug() << "Intersection successful?     " << toString(success);

    qDebug() << "";

    qDebug() << "Construct NaifDskShape object from cube labels with ElevationModel=DSK file.";    

    Pvl pvlWithElevation("./st_2530292409_v_DskElevationModel.lbl");

             << QVector<double>::fromStdVector(shapeModelFromPvlElevation.normal());

    qDebug() << "";

    qDebug() << "================================= Error Throws ==================================";

    qDebug() << "Construct NaifDskShape object from cube labels with ShapeModel=Null.";    

    try {