ImagePolygon.cpp

 
/* SPDX-License-Identifier: CC0-1.0 */
 
#include <string>
#include <iostream>
#include <vector>
 
#include <QDebug>
 
#include <geos/geom/Geometry.h>
#include <geos/geom/Polygon.h>
#include <geos/geom/CoordinateSequence.h>
#include <geos/algorithm/LineIntersector.h>
#include <geos/util/IllegalArgumentException.h>
#include <geos/util/TopologyException.h>
#include <geos/util/GEOSException.h>
#include <geos/io/WKTReader.h>
#include <geos/io/WKTWriter.h>
#include <geos/operation/distance/DistanceOp.h>
 
#include "ImagePolygon.h"
#include "IString.h"
#include "SpecialPixel.h"
#include "PolygonTools.h"
 
using namespace std;
 
namespace Isis {

  ImagePolygon::ImagePolygon() {
    p_polygons = NULL;
 
    p_cube = NULL;
 
    m_leftCoord = NULL;
    m_rightCoord = NULL;
    m_topCoord = NULL;
    m_botCoord = NULL;
 
    p_cubeStartSamp = 1;
    p_cubeStartLine = 1;
 
    p_emission = 180.0;
    p_incidence = 180.0;
 
    p_subpixelAccuracy = 50; //An accuracte and quick number
 
    p_ellipsoid = false;
  }
  ImagePolygon::ImagePolygon() {…}
 

  ImagePolygon::ImagePolygon(Blob &blob) : ImagePolygon() {
    p_polyStr = string(blob.getBuffer(), blob.Size());
 
    geos::io::WKTReader *wkt = new geos::io::WKTReader(&(*globalFactory));
    p_polygons = PolygonTools::MakeMultiPolygon(wkt->read(p_polyStr).release());
 
    p_pts = new geos::geom::CoordinateSequence;
 
//    for (auto poly : *p_polygons) {
    for(unsigned int g = 0; g < p_polygons->getNumGeometries(); ++g) {
      const geos::geom::Polygon *poly =
          dynamic_cast<const geos::geom::Polygon *>(p_polygons->getGeometryN(g));
      geos::geom::CoordinateSequence coordArray = geos::geom::CoordinateSequence(*(poly->getCoordinates()));
      for (size_t i = 0; i < coordArray.getSize(); i++) {
        p_pts->add(geos::geom::Coordinate(coordArray.getAt(i)));
      }
    }
  }
  ImagePolygon::ImagePolygon(Blob &blob) : ImagePolygon() {…}
 

  ImagePolygon::~ImagePolygon() {
    delete p_polygons;
    p_polygons = NULL;
 
    p_cube = NULL;
 
    delete m_leftCoord;
    m_leftCoord = NULL;
 
    delete m_rightCoord;
    m_rightCoord = NULL;
 
    delete m_topCoord;
    m_topCoord = NULL;
 
    delete m_botCoord;
    m_botCoord = NULL;
  }
  ImagePolygon::~ImagePolygon() {…}
 

  Camera * ImagePolygon::initCube(Cube &cube, int ss, int sl,
                                  int ns, int nl, int band) {
    p_gMap = new UniversalGroundMap(cube);
    p_gMap->SetBand(band);
 
    p_cube = &cube;
 
    Camera *cam = NULL;
    p_isProjected = false;
 
    try {
      cam = cube.camera();
    }
    catch(IException &camError) {
      try {
        cube.projection();
        p_isProjected = true;
      }
      catch(IException &projError) {
        QString msg = "Can not create polygon, ";
        msg += "cube [" + cube.fileName();
        msg += "] is not a camera or map projection";
 
        IException polyError(IException::User, msg, _FILEINFO_);
 
        polyError.append(camError);
        polyError.append(projError);
 
        throw polyError;
      }
    }
    if (cam != NULL) p_isProjected = cam->HasProjection();
 
    //  Create brick for use in SetImage
    p_brick = new Brick(1, 1, 1, cube.pixelType());
 
    //------------------------------------------------------------------------
    //  Save cube number of samples and lines for later use.
    //------------------------------------------------------------------------
    p_cubeSamps = cube.sampleCount();
    p_cubeLines = cube.lineCount();
 
    if (ns != 0) {
      p_cubeSamps = std::min(p_cubeSamps, ss + ns);
    }
 
    if (nl != 0) {
      p_cubeLines = std::min(p_cubeLines, sl + nl);
    }
 
    p_cubeStartSamp = ss;
    p_cubeStartLine = sl;
 
    if (p_ellipsoid && IsLimb() && p_gMap->Camera()) {
      try {
        p_gMap->Camera()->IgnoreElevationModel(true);
      }
      catch(IException &) {
        std::string msg = "Cannot use an ellipsoid shape model";
        msg += " on a limb image without a camera.";
        throw IException(IException::User, msg, _FILEINFO_);
      }
    }
 
    return cam;
  }
  Camera * ImagePolygon::initCube(Cube &cube, int ss, int sl, {…}
 

  void ImagePolygon::Create(Cube &cube, int sinc, int linc,
                            int ss, int sl, int ns, int nl, int band,
                            bool increasePrecision) {
 
    Camera *cam = NULL;
 
    if (sinc < 1 || linc < 1) {
      std::string msg = "Sample and line increments must be 1 or greater";
      throw IException(IException::User, msg, _FILEINFO_);
    }
 
    cam = initCube(cube, ss, sl, ns, nl, band);
 
    // Reduce the increment size to find a valid polygon
    bool polygonGenerated = false;
    while (!polygonGenerated) {
      try {
        p_sampinc = sinc;
        p_lineinc = linc;
 
        p_pts = NULL;
        p_pts = new geos::geom::CoordinateSequence();
 
        WalkPoly();
 
        polygonGenerated = true;
      }
      catch (IException &e) {
        delete p_pts;
 
        sinc = sinc * 2 / 3;
        linc = linc * 2 / 3;
 
        if (increasePrecision && (sinc > 1 || linc > 1)) {
        }
        else {
          e.print(); // This should be a NAIF error
          QString msg = "Cannot find polygon for image "
              "[" + cube.fileName() + "]: ";
          msg += increasePrecision ? "Cannot increase precision any further" :
              "The increment/step size might be too large";
          throw IException(IException::User, msg, _FILEINFO_);
        }
      }
    }
 
    /*------------------------------------------------------------------------
    /  If image contains 0/360 boundary, the polygon needs to be split up
    /  into multi polygons.
    /-----------------------------------------------------------------------*/
    if (cam) {
      Pvl defaultMap;
      cam->BasicMapping(defaultMap);
    }
 
    // Create the polygon, fixing if needed
    Fix360Poly();
 
    if (p_brick != 0) delete p_brick;
 
    if (p_gMap->Camera())
      p_gMap->Camera()->IgnoreElevationModel(false);
  }
  void ImagePolygon::Create(Cube &cube, int sinc, int linc, {…}
 
 
  void ImagePolygon::Create(std::vector<std::vector<double>> polyCoordinates) {
    p_pts = new geos::geom::CoordinateSequence();
 
    for (std::vector<double> coord : polyCoordinates) {
      p_pts->add(geos::geom::Coordinate(coord[0], coord[1]));
    }
 
    std::vector<const geos::geom::Geometry *> *polys = new std::vector<const geos::geom::Geometry *>;
    const geos::geom::Polygon *poly = globalFactory->createPolygon(globalFactory->createLinearRing(*p_pts)).release();
    polys->push_back(poly->clone().release());
    // createMultiPolygon takes ownership of polys argument
    p_polygons = globalFactory->createMultiPolygon(*polys).release();
 
    Fix360Poly();
  }
 

  geos::geom::Coordinate ImagePolygon::FindNextPoint(geos::geom::Coordinate *currentPoint,
      geos::geom::Coordinate lastPoint,
      int recursionDepth) {
    double x = lastPoint.x - currentPoint->x;
    double y = lastPoint.y - currentPoint->y;
    geos::geom::Coordinate result;
 
    // Check to see if depth is too deep (walked all the way around and found nothing)
    if (recursionDepth > 6) {
      return *currentPoint;
    }
 
    // Check and walk in appropriate direction
    if (x == 0.0 && y == 0.0) {  // Find the starting point on an image
      for (int line = -1 * p_lineinc; line <= 1 * p_lineinc; line += p_lineinc) {
        for (int samp = -1 * p_sampinc; samp <= 1 * p_sampinc; samp += p_sampinc) {
          double s = currentPoint->x + samp;
          double l = currentPoint->y + line;
          // Try the next left hand rule point if (s,l) does not produce a
          // lat/long or it is not on the image.
          if (!InsideImage(s, l) || !SetImage(s, l)) {
            geos::geom::Coordinate next(s, l);
            return FindNextPoint(currentPoint, next);
          }
        }
      }
 
      std::string msg = "Unable to create image footprint. Starting point is not on the edge of the image.";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    else if (x < 0 && y < 0) {  // current is top left
      geos::geom::Coordinate next(currentPoint->x, currentPoint->y - 1 * p_lineinc);
      MoveBackInsideImage(next.x, next.y, 0, -p_lineinc);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else if (x == 0.0 && y < 0) {  // current is top
      geos::geom::Coordinate next(currentPoint->x + 1 * p_sampinc, currentPoint->y - 1 * p_lineinc);
      MoveBackInsideImage(next.x, next.y, p_sampinc, -p_lineinc);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else if (x > 0 && y < 0) {  // current is top right
      geos::geom::Coordinate next(currentPoint->x + 1 * p_sampinc, currentPoint->y);
      MoveBackInsideImage(next.x, next.y, p_sampinc, 0);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else if (x > 0 && y == 0.0) {  // current is right
      geos::geom::Coordinate next(currentPoint->x + 1 * p_sampinc, currentPoint->y + 1 * p_lineinc);
      MoveBackInsideImage(next.x, next.y, p_sampinc, p_lineinc);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else if (x > 0 && y > 0) {  // current is bottom right
      geos::geom::Coordinate next(currentPoint->x, currentPoint->y + 1 * p_lineinc);
      MoveBackInsideImage(next.x, next.y, 0, p_lineinc);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else if (x == 0.0 && y > 0) {  // current is bottom
      geos::geom::Coordinate next(currentPoint->x - 1 * p_sampinc, currentPoint->y + 1 * p_lineinc);
      MoveBackInsideImage(next.x, next.y, -p_sampinc, p_lineinc);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else if (x < 0 && y > 0) {   // current is bottom left
      geos::geom::Coordinate next(currentPoint->x - 1 * p_sampinc, currentPoint->y);
      MoveBackInsideImage(next.x, next.y, -p_sampinc, 0);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else if (x < 0 && y == 0.0) {  // current is left
      geos::geom::Coordinate next(currentPoint->x - 1 * p_sampinc, currentPoint->y - 1 * p_lineinc);
      MoveBackInsideImage(next.x, next.y, -p_sampinc, -p_lineinc);
      if (!recursionDepth || !InsideImage(next.x, next.y) || !SetImage(next.x , next.y)) {
        result = FindNextPoint(currentPoint, next, recursionDepth + 1);
      }
      else {
        result = FindBestPoint(currentPoint, next, lastPoint);
      }
    }
    else {
      std::string msg = "Unable to create image footprint. Error walking image.";
      throw IException(IException::Unknown, msg, _FILEINFO_);
    }
 
 
    return result;
  }
  geos::geom::Coordinate ImagePolygon::FindNextPoint(geos::geom::Coordinate *currentPoint, {…}
 

  void ImagePolygon::MoveBackInsideImage(double &sample, double &line, double sinc, double linc) {
    // snap to centers of pixels!
 
    // Starting sample to snap to
    const double startSample = p_cubeStartSamp;
    // Ending sample to snap to
    const double endSample = p_cubeSamps;
    // Starting line to snap to
    const double startLine = p_cubeStartLine;
    // Ending line to snap to
    const double endLine = p_cubeLines;
    // Original sample for this point (before sinc)
    const double origSample = sample - sinc;
    // Original line for this point (before linc)
    const double origLine = line - linc;
 
    // We moved left off the image - snap to the edge
    if (sample < startSample && sinc < 0) {
      // don't snap if we started at the edge
      if (origSample == startSample) {
        return;
      }
 
      sample = startSample;
    }
 
    // We moved right off the image - snap to the edge
    if (sample > endSample && sinc > 0) {
      // don't snap if we started at the edge
      if (origSample == endSample) {
        return;
      }
 
      sample = endSample;
    }
 
    // We moved up off the image - snap to the edge
    if (line < startLine && linc < 0) {
      // don't snap if we started at the edge
      if (origLine == startLine) {
        return;
      }
 
      line = startLine;
    }
 
    // We moved down off the image - snap to the edge
    if (line > endLine && linc > 0) {
      // don't snap if we started at the edge
      if (fabs(origLine - endLine) < 0.5) {
        return;
      }
 
      line = endLine;
    }
 
    return;
  }
  void ImagePolygon::MoveBackInsideImage(double &sample, double &line, double sinc, double linc) {…}
 

  bool ImagePolygon::InsideImage(double sample, double line) {
    return (sample >= p_cubeStartSamp - 0.5 &&
            line > p_cubeStartLine - 0.5 &&
            sample <= p_cubeSamps + 0.5 &&
            line <= p_cubeLines + 0.5);
  }
  bool ImagePolygon::InsideImage(double sample, double line) {…}
 

  geos::geom::Coordinate ImagePolygon::FindFirstPoint() {
    // @todo: Brute force method, should be improved
    for (int sample = p_cubeStartSamp; sample <= p_cubeSamps; sample++) {
      for (int line = p_cubeStartLine; line <= p_cubeLines; line++) {
        if (SetImage(sample, line)) {
          // An outlier check.  Make sure that the pixel we use to start
          // constructing a polygon is not surrounded by a bunch of invalid
          // positions.
          geos::geom::Coordinate firstPoint(sample, line);
          geos::geom::Coordinate lastPoint = firstPoint;
          if (!firstPoint.equals(FindNextPoint(&firstPoint, lastPoint))) {
            return firstPoint;
          }
        }
      }
    }
 
    // Check to make sure a point was found
    std::string msg = "No lat/lon data found for image";
    throw IException(IException::User, msg, _FILEINFO_);
  }
  geos::geom::Coordinate ImagePolygon::FindFirstPoint() {…}
 

  double ImagePolygon::validSampleDim() {
    double result = 0.0;
 
    calcImageBorderCoordinates();
    if (m_rightCoord && m_leftCoord)
      result = m_rightCoord->x - m_leftCoord->x + 1;
 
    return result;
  }
  double ImagePolygon::validSampleDim() {…}
 

  double ImagePolygon::validLineDim() {
    double result = 0.0;
 
    calcImageBorderCoordinates();
    if (m_topCoord && m_botCoord)
      result = m_botCoord->y - m_topCoord->y + 1;
 
    return result;
  }
  double ImagePolygon::validLineDim() {…}
 

  void ImagePolygon::calcImageBorderCoordinates() {
    
    for (int line = p_cubeStartLine; !m_leftCoord && line <= p_cubeLines; line++) {
      for (int sample = p_cubeStartSamp; !m_leftCoord && sample <= p_cubeSamps; sample++) {
        if (SetImage(sample, line)) {
          m_leftCoord = new geos::geom::Coordinate(sample, line);
        }
      }
    }
 
    if (m_leftCoord) {
      for (int line = p_cubeStartLine; !m_rightCoord && line <= p_cubeLines; line++) {
        for (int sample = p_cubeSamps; !m_rightCoord && sample >= m_leftCoord->x; sample--) {
          if (SetImage(sample, line)) {
            m_rightCoord = new geos::geom::Coordinate(sample, line);
          }
        }
      }
    }
 
    if (m_leftCoord && m_rightCoord) {
      for (int sample = (int)m_leftCoord->x; !m_topCoord && sample <= m_rightCoord->x; sample++) {
        for (int line = 1; !m_topCoord && line <= p_cubeLines; line++) {
          if (SetImage(sample, line)) {
            m_topCoord = new geos::geom::Coordinate(sample, line);
          }
        }
      }
    }
 
    if (m_leftCoord && m_rightCoord && m_topCoord) {
      for (int sample = (int)m_leftCoord->x; !m_botCoord && sample <= m_rightCoord->x; sample++) {
        for (int line = p_cube->lineCount(); !m_botCoord && line >= m_topCoord->y; line--) {
          if (SetImage(sample, line)) {
            m_botCoord = new geos::geom::Coordinate(sample, line);
          }
        }
      }
    }
  }
  void ImagePolygon::calcImageBorderCoordinates() {…}
 

  void ImagePolygon::WalkPoly() {
    vector<geos::geom::Coordinate> points;
    double lat, lon, prevLat, prevLon;
 
    // Find the edge of the polygon
    geos::geom::Coordinate firstPoint = FindFirstPoint();
 
    points.push_back(firstPoint);
    //************************
    // Start walking the edge
    //************************
 
    // set up for intialization
    geos::geom::Coordinate currentPoint = firstPoint;
    geos::geom::Coordinate lastPoint = firstPoint;
    geos::geom::Coordinate tempPoint;
 
    do {
      tempPoint = FindNextPoint(&currentPoint, lastPoint);
 
      // First check if the distance is within range of skipping
      bool snapToFirstPoint = true;
 
      // Never needs to find firstPoint on incements of 1
      snapToFirstPoint &= (p_sampinc != 1  &&  p_lineinc != 1);
 
      // Prevents catching the first point as the last
      snapToFirstPoint &= (points.size() > 2);
 
      // This method fails for steps larger than line/sample length
      snapToFirstPoint &= (p_sampinc < p_cubeSamps && p_lineinc < p_cubeLines);
 
      // Checks for appropriate distance without sqrt() call
      int minStepSize = std::min(p_sampinc, p_lineinc);
      snapToFirstPoint &= (DistanceSquared(&currentPoint, &firstPoint) < (minStepSize * minStepSize));
 
      // Searches for skipped firstPoint due to a large pixinc, by using a pixinc of 1
      if (snapToFirstPoint) {
        tempPoint = firstPoint;
      }
      // If pixinc is greater than line or sample dimention, then we could
      // skip firstPoint. This checks for that case.
      else if (p_sampinc > p_cubeSamps || p_lineinc > p_cubeLines) {
        // This is not expensive because incement must be large
        for (int pt = 0; pt < (int)points.size(); pt ++) {
          if (points[pt].equals(tempPoint)) {
            tempPoint = firstPoint;
            break;
          }
        }
      }
      // Failed to find the next point
      if (tempPoint.equals(currentPoint)) {
        geos::geom::Coordinate oldDuplicatePoint = tempPoint;
 
        // Init vars for first run through the loop
        tempPoint = lastPoint;
        lastPoint = currentPoint;
        currentPoint = tempPoint;
 
        // Must be 3 (not 2) to prevent the revisit of the starting point,
        // resulting in an infinite loop
        if (points.size() < 3) {
          std::string msg = "Failed to find next point in the image.";
          throw IException(IException::Programmer, msg, _FILEINFO_);
        }
 
        // remove last point from the list
        points.pop_back();
 
        tempPoint = FindNextPoint(&currentPoint, lastPoint, 1);
 
        if (tempPoint.equals(currentPoint) || tempPoint.equals(oldDuplicatePoint)) {
          std::string msg = "Failed to find next valid point in the image.";
          throw IException(IException::Programmer, msg, _FILEINFO_);
        }
      }
 
 
      // Check for triangle cycles and try to fix
      if ((p_sampinc > 1  ||  p_lineinc > 1) && points.size() >= 3) {
        if (points[points.size()-3].x == tempPoint.x &&
            points[points.size()-3].y == tempPoint.y) {
          // Remove the triangle from the list
          points.pop_back();
          points.pop_back();
          points.pop_back();
          // Reset the current (to be last) point
          currentPoint = points[points.size()-1];
          // change increment to prevent randomly bad pixels in the image
          if (p_sampinc > 1) p_sampinc --;
          if (p_lineinc > 1) p_lineinc --;
        }

        if (points.size() > 250) {
          int cycleStart = 0;
          int cycleEnd = 0;
 
          for (unsigned int pt = 1; pt < points.size() && cycleStart == 0; pt ++) {
            for (unsigned int check = pt + 1; check < points.size() && cycleStart == 0; check ++) {
              if (points[pt] == points[check]) {
                cycleStart = pt;
                cycleEnd = check;
              }
            }
          }
 
          // If a cycle was found, make it the polygon
          if (cycleStart != 0) {
            vector<geos::geom::Coordinate> cyclePoints;
            for (int pt = cycleStart; pt <= cycleEnd; pt ++) {
              cyclePoints.push_back(points[pt]);
            }
 
            points = cyclePoints;
            break;
          }
        }
 
      }
 
      lastPoint = currentPoint;
      currentPoint = tempPoint;
      points.push_back(currentPoint);
 
    }
    while (!currentPoint.equals(firstPoint));
 
    if (points.size() <= 3) {
      std::string msg = "Failed to find enough points on the image.";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
 
    FindSubpixel(points);
 
    prevLat = 0;
    prevLon = 0;
    // this vector stores crossing points, where the image crosses the
    // meridian. It stores the first coordinate of the pair in its vector
    vector<geos::geom::Coordinate> *crossingPoints = new vector<geos::geom::Coordinate>;
    for (unsigned int i = 0; i < points.size(); i++) {
      geos::geom::Coordinate *temp = &(points.at(i));
      SetImage(temp->x, temp->y);
      lon = p_gMap->UniversalLongitude();
      lat = p_gMap->UniversalLatitude();
      if (abs(lon - prevLon) >= 180 && i != 0) {
        crossingPoints->push_back(geos::geom::Coordinate(prevLon, prevLat));
      }
      p_pts->add(geos::geom::Coordinate(lon, lat));
      prevLon = lon;
      prevLat = lat;
    }
 
 
    // Checks for self-intersection and attempts to correct
    geos::geom::CoordinateSequence *tempPts = new geos::geom::CoordinateSequence();
 
    // Gets the starting, second, second to last, and last points to check for validity
    tempPts->add(geos::geom::Coordinate((*p_pts)[0].x, (*p_pts)[0].y));
    tempPts->add(geos::geom::Coordinate((*p_pts)[1].x, (*p_pts)[1].y));
    tempPts->add(geos::geom::Coordinate((*p_pts)[p_pts->size()-3].x, (*p_pts)[p_pts->size()-3].y));
    tempPts->add(geos::geom::Coordinate((*p_pts)[p_pts->size()-2].x, (*p_pts)[p_pts->size()-2].y));
    tempPts->add(geos::geom::Coordinate((*p_pts)[0].x, (*p_pts)[0].y));
 
    geos::geom::Polygon *tempPoly = globalFactory->createPolygon
                                    (globalFactory->createLinearRing(*tempPts)).release();
 
    // Remove the last point of the sequence if it produces invalid polygons
    if (!tempPoly->isValid()) {
      std::vector<geos::geom::Coordinate> coords;
      p_pts->toVector(coords);
      coords.erase(coords.begin() + p_pts->size() - 2);
      p_pts->setPoints(coords);
    }
 
    delete tempPts;
    tempPts = NULL;
    // end self-intersection check
 
    FixPolePoly(crossingPoints);
    delete crossingPoints;
    crossingPoints = NULL;
  }
  void ImagePolygon::WalkPoly() {…}
 

  void ImagePolygon::FixPolePoly(std::vector<geos::geom::Coordinate> *crossingPoints) {
    // We currently do not support both poles in one image
    bool hasNorthPole = false;
    bool hasSouthPole = false;
 
    if (p_gMap->SetUniversalGround(90, 0)) {
      double nPoleSample = Null;
      double nPoleLine = Null;
 
      if (p_gMap->Projection()) {
        nPoleSample = p_gMap->Projection()->WorldX();
        nPoleLine = p_gMap->Projection()->WorldY();
      }
      else if (p_gMap->Camera()) {
        nPoleSample = p_gMap->Camera()->Sample();
        nPoleLine = p_gMap->Camera()->Line();
      }
 
      if (nPoleSample >= 0.5 && nPoleLine >= 0.5 &&
         nPoleSample <= p_cube->sampleCount() + 0.5 &&
         nPoleLine <= p_cube->lineCount() + 0.5 &&
         SetImage(nPoleSample, nPoleLine)) {
        hasNorthPole = true;
      }
    }
 
    if (p_gMap->SetUniversalGround(-90, 0)) {
      double sPoleSample = Null;
      double sPoleLine = Null;
 
      if (p_gMap->Projection()) {
        sPoleSample = p_gMap->Projection()->WorldX();
        sPoleLine = p_gMap->Projection()->WorldY();
      }
      else if (p_gMap->Camera()) {
        sPoleSample = p_gMap->Camera()->Sample();
        sPoleLine = p_gMap->Camera()->Line();
      }
 
      if (sPoleSample >= 0.5 && sPoleLine >= 0.5 &&
         sPoleSample <= p_cube->sampleCount() + 0.5 &&
         sPoleLine <= p_cube->lineCount() + 0.5 &&
         SetImage(sPoleSample, sPoleLine)) {
        hasSouthPole = true;
      }
    }
 
    if (hasNorthPole && hasSouthPole) {
      std::string msg = "Unable to create image footprint because image has both poles";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    else if (crossingPoints->size() == 0) {
      // No crossing points
      return;
    }
 
    if (hasNorthPole) {
      p_gMap->SetUniversalGround(90, 0);
 
      // If the (north) pole is settable but not within proper angles,
      //  then the polygon does not contain the (north) pole when the cube does
      if (p_gMap->Camera() &&
         p_gMap->Camera()->EmissionAngle() > p_emission) {
        return;
      }
      if (p_gMap->Camera() &&
         p_gMap->Camera()->IncidenceAngle() > p_incidence) {
        return;
      }
    }
    else if (hasSouthPole) {
      p_gMap->SetUniversalGround(-90, 0);
 
      // If the (south) pole is settable but not within proper angles,
      //  then the polygon does not contain the (south) pole when the cube does
      if (p_gMap->Camera() &&
         p_gMap->Camera()->EmissionAngle() > p_emission) {
        return;
      }
      if (p_gMap->Camera() &&
         p_gMap->Camera()->IncidenceAngle() > p_incidence) {
        return;
      }
    }
 
    geos::geom::Coordinate *closestPoint = &crossingPoints->at(0);
    geos::geom::Coordinate *pole = NULL;
 
    // Setup the right pole
    if (hasNorthPole) {
      pole = new geos::geom::Coordinate(0, 90);
    }
    else if (hasSouthPole) {
      pole = new geos::geom::Coordinate(0, -90);
    }
    else if (crossingPoints->size() % 2 == 1) {
      geos::geom::Coordinate nPole(0, 90);
      double nDist = DBL_MAX;
      geos::geom::Coordinate sPole(0, -90);
      double sDist = DBL_MAX;
 
      for (unsigned int index = 0; index < p_pts->size(); index ++) {
        double north = DistanceSquared(&nPole, &((*p_pts)[index]));
        if (north < nDist) {
          nDist = north;
        }
        double south = DistanceSquared(&sPole, &((*p_pts)[index]));
        if (south < sDist) {
          sDist = south;
        }
      }
 
      if (sDist < nDist) {
        pole = new geos::geom::Coordinate(0, -90);
      }
      else {
        pole = new geos::geom::Coordinate(0, 90);
      }
    }
 
    // Skip the fix if no pole was determined
    if (pole == NULL) {
      return;
    }
 
    // Find where the pole needs to be split
    double closestDistance = DBL_MAX;
    for (unsigned int i = 0; i < crossingPoints->size(); i++) {
      geos::geom::Coordinate *temp = &crossingPoints->at(i);
      double tempDistance;
      // Make sure the Lat is as close to 0 as possible for a correct distance
      if (temp->x > 180) {
        double mod = 0.0;
        while ((temp->x - mod) > 180) mod += 360.0;
 
        // Create the modified Point, create a pointer to it, and find the distance
        geos::geom::Coordinate modPointMem = geos::geom::Coordinate(temp->x - mod, temp->y);
        geos::geom::Coordinate *modPoint = &modPointMem;
        tempDistance = DistanceSquared(modPoint, pole);
      }
      else {
        tempDistance = DistanceSquared(temp, pole);
      }
      if (tempDistance < closestDistance) {
        closestDistance = tempDistance;
        closestPoint = temp;
      }
    }
 
    if (closestDistance == DBL_MAX) {
      std::string msg = "Image contains a pole but did not detect a meridian crossing!";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
 
    // split image at the pole
    geos::geom::CoordinateSequence *new_points = new geos::geom::CoordinateSequence();
    for (unsigned int i = 0; i < p_pts->size(); i++) {
      geos::geom::Coordinate temp = p_pts->getAt(i);
      new_points->add(temp);
      if (temp.equals(*closestPoint)) {
        // Setup direction
        if (i + 1 != p_pts->size()) { // Prevent overflow exception
          double fromLon, toLon;
          if ((p_pts->getAt(i + 1).x - closestPoint->x) > 0) {
            fromLon = 0.0;
            toLon   = 360.0;
          }
          else {
            fromLon = 360.0;
            toLon   = 0.0;
          }
 
          geos::algorithm::LineIntersector lineIntersector;
          geos::geom::Coordinate crossingPoint;
          geos::geom::Coordinate nPole(0.0, 90.0);
          geos::geom::Coordinate sPole(0.0, -90.0);
          double dist = DBL_MAX;
 
          for (int num = 0; num < 2 && dist > 180.0; num ++) {
            nPole = geos::geom::Coordinate(num * 360.0, 90.0);
            sPole = geos::geom::Coordinate(num * 360.0, -90.0);
 
            if (temp.x > 0.0  &&  p_pts->getAt(i + 1).x > 0.0) {
              crossingPoint = geos::geom::Coordinate(p_pts->getAt(i + 1).x - 360.0 + (num * 720.0), p_pts->getAt(i + 1).y);
            }
            else if (temp.x < 0.0  &&  p_pts->getAt(i + 1).x < 0.0) { // This should never happen
              crossingPoint = geos::geom::Coordinate(p_pts->getAt(i + 1).x + 360.0 - (num * 720.0), p_pts->getAt(i + 1).y);
            }
 
            dist = std::sqrt(DistanceSquared(&temp, &crossingPoint));
          }
 
          lineIntersector.computeIntersection(nPole, sPole, temp, crossingPoint);
 
          if (lineIntersector.hasIntersection()) {
            const geos::geom::Coordinate &intersection = lineIntersector.getIntersection(0);
 
            // Calculate the latituded of the points along the meridian
            if (pole->y < intersection.y) {
              dist = -dist;
            }
            vector<double> lats;
            double maxLat = std::max(intersection.y, pole->y);
            double minLat = std::min(intersection.y, pole->y);
            for (double lat = intersection.y + dist; lat < maxLat  &&  lat > minLat; lat += dist) {
              lats.push_back(lat);
            }
 
            // Add the new points
            new_points->add(geos::geom::Coordinate(fromLon, intersection.y));
            for (int lat = 0; lat < (int)lats.size(); lat ++) {
              new_points->add(geos::geom::Coordinate(fromLon, lats[lat]));
            }
            new_points->add(geos::geom::Coordinate(fromLon, pole->y));
            new_points->add(geos::geom::Coordinate(toLon, pole->y));
            for (int lat = lats.size() - 1; lat >= 0; lat --) {
              new_points->add(geos::geom::Coordinate(toLon, lats[lat]));
            }
            new_points->add(geos::geom::Coordinate(toLon, intersection.y));
          }
          else {
            std::string msg = "Image contains a pole but could not determine a meridian crossing!";
            throw IException(IException::Programmer, msg, _FILEINFO_);
          }
 
        }
      }
    }
    delete p_pts;
    p_pts = new_points;
    delete pole;
  }
  void ImagePolygon::FixPolePoly(std::vector<geos::geom::Coordinate> *crossingPoints) {…}
 

  bool ImagePolygon::SetImage(const double sample, const double line) {
    bool found = false;
    if (!p_isProjected) {
      found = p_gMap->SetImage(sample, line);
      if (!found) {
        return false;
      }
      else {
        // Check for valid emission and incidence
        try {
          if (p_gMap->Camera() &&
             p_gMap->Camera()->EmissionAngle() > p_emission) {
            return false;
          }
          if (p_gMap->Camera() &&
             p_gMap->Camera()->IncidenceAngle() > p_incidence) {
            return false;
          }
        }
        catch(IException &error) {
        }

        //  Make sure we can go back to image coordinates
        //  This is done because some camera models due to distortion, get
        //  a lat/lon for samp/line=1:1, but entering that lat/lon does
        //  not return samp/line =1:1. Ie.  moc WA global images
        //double lat = p_gMap->UniversalLatitude();
        //double lon = p_gMap->UniversalLongitude();
        //return p_gMap->SetUniversalGround(lat,lon);
 
        return found;
      }
    }
    else {
      // If projected, make sure the pixel DN is valid before worrying about
      //  geometry.
      p_brick->SetBasePosition((int)sample, (int)line, 1);
      p_cube->read(*p_brick);
      if (Isis::IsNullPixel((*p_brick)[0])) {
        return false;
      }
      else {
        return p_gMap->SetImage(sample, line);
      }
    }
  }
  bool ImagePolygon::SetImage(const double sample, const double line) {…}
 

  void ImagePolygon::Fix360Poly() {
    bool convertLon = false;
    bool negAdjust = false;
    bool newCoords = false;  //  coordinates have been adjusted
    geos::geom::CoordinateSequence *newLonLatPts = new geos::geom::CoordinateSequence();
    double lon, lat;
    double lonOffset = 0;
    double prevLon = p_pts->getAt(0).x;
    double prevLat = p_pts->getAt(0).y;
 
    newLonLatPts->add(geos::geom::Coordinate(prevLon, prevLat));
    double dist = 0.0;
    for (unsigned int i = 1; i < p_pts->getSize(); i++) {
      lon = p_pts->getAt(i).x;
      lat = p_pts->getAt(i).y;
      
      // check to see if you just crossed the Meridian
      if (abs(lon - prevLon) > 180 && (prevLat != 90 && prevLat != -90)) {
        newCoords = true;
        // if you were already converting then stop (crossed Meridian even number of times)
        if (convertLon) {
          convertLon = false;
          lonOffset = 0;
        }
        else {   // Need to start converting again, deside how to adjust coordinates
          if ((lon - prevLon) > 0) {
            lonOffset = -360.;
            negAdjust = true;
          }
          else if ((lon - prevLon) < 0) {
            lonOffset = 360.;
            negAdjust = false;
          }
          convertLon = true;
        }
 
 
      }
 
      // Change to a minimum calculation
      if (newCoords  &&  dist == 0.0) {
        double longitude = (lon + lonOffset) - prevLon;
        double latitude = lat - prevLat;
        dist = std::sqrt((longitude * longitude) + (latitude * latitude));
      }
 
      // add coord
      newLonLatPts->add(geos::geom::Coordinate(lon + lonOffset, lat));
 
      // set current to old
      prevLon = lon;
      prevLat = lat;
    }
 
    // Nothing was done so return
    if (!newCoords) {
      geos::geom::Polygon *newPoly = globalFactory->createPolygon
                                     (globalFactory->createLinearRing(*newLonLatPts)).release();
      p_polygons = PolygonTools::MakeMultiPolygon(newPoly);
      delete newLonLatPts;
      return;
    }
 
    // bisect into seperate polygons
    try {
      geos::geom::Polygon *newPoly = globalFactory->createPolygon
                                     (globalFactory->createLinearRing(*newLonLatPts)).release();
 
      geos::geom::CoordinateSequence *pts = new geos::geom::CoordinateSequence();
      geos::geom::CoordinateSequence *pts2 = new geos::geom::CoordinateSequence();
 
      // Depending on direction of compensation bound accordingly
      //***************************************************
 
      // please verify correct if you change these values
      //***************************************************
      if (negAdjust) {
        pts->add(geos::geom::Coordinate(0., 90.));
        pts->add(geos::geom::Coordinate(-360., 90.));
        pts->add(geos::geom::Coordinate(-360., -90.));
        pts->add(geos::geom::Coordinate(0., -90.));
        for (double lat = -90.0 + dist; lat < 90.0; lat += dist) {
          pts->add(geos::geom::Coordinate(0.0, lat));
        }
        pts->add(geos::geom::Coordinate(0., 90.));
        pts2->add(geos::geom::Coordinate(0., 90.));
        pts2->add(geos::geom::Coordinate(360., 90.));
        pts2->add(geos::geom::Coordinate(360., -90.));
        pts2->add(geos::geom::Coordinate(0., -90.));
        for (double lat = -90.0 + dist; lat < 90.0; lat += dist) {
          pts2->add(geos::geom::Coordinate(0.0, lat));
        }
        pts2->add(geos::geom::Coordinate(0., 90.));
      }
      else {
        pts->add(geos::geom::Coordinate(360., 90.));
        pts->add(geos::geom::Coordinate(720., 90.));
        pts->add(geos::geom::Coordinate(720., -90.));
        pts->add(geos::geom::Coordinate(360., -90.));
        for (double lat = -90.0 + dist; lat < 90.0; lat += dist) {
          pts->add(geos::geom::Coordinate(360.0, lat));
        }
        pts->add(geos::geom::Coordinate(360., 90.));
        pts2->add(geos::geom::Coordinate(360., 90.));
        pts2->add(geos::geom::Coordinate(0., 90.));
        pts2->add(geos::geom::Coordinate(0., -90.));
        pts2->add(geos::geom::Coordinate(360., -90.));
        for (double lat = -90.0 + dist; lat < 90.0; lat += dist) {
          pts2->add(geos::geom::Coordinate(360.0, lat));
        }
        pts2->add(geos::geom::Coordinate(360., 90.));
      }
 
      geos::geom::Polygon *boundaryPoly = globalFactory->createPolygon
                                          (globalFactory->createLinearRing(*pts)).release();
      geos::geom::Polygon *boundaryPoly2 = globalFactory->createPolygon
                                           (globalFactory->createLinearRing(*pts2)).release();
      /*------------------------------------------------------------------------
      /  Intersecting the original polygon (converted coordinates) with the
      /  boundary polygons will create the multi polygons with the converted coordinates.
      /  These will need to be converted back to the original coordinates.
      /-----------------------------------------------------------------------*/
      geos::geom::Geometry *intersection = PolygonTools::Intersect(newPoly, boundaryPoly);
      geos::geom::MultiPolygon *convertPoly = PolygonTools::MakeMultiPolygon(intersection);
      delete intersection;
 
      intersection = PolygonTools::Intersect(newPoly, boundaryPoly2);
      geos::geom::MultiPolygon *convertPoly2 = PolygonTools::MakeMultiPolygon(intersection);
      delete intersection;
 
      /*------------------------------------------------------------------------
      / Adjust points created in the negative space or >360 space to be back in
      / the 0-360 world.  This will always only need to be done on convertPoly.
      / Then add geometries to finalpolys.
      /-----------------------------------------------------------------------*/
      std::vector<const geos::geom::Geometry *> *finalpolys = new std::vector<const geos::geom::Geometry *>;
      const geos::geom::Geometry *newGeom = NULL;
 
      for (size_t i = 0; i < convertPoly->getNumGeometries(); i++) {
        newGeom = (convertPoly->getGeometryN(i))->clone().release();
        geos::geom::CoordinateSequence *pts3 = convertPoly->getGeometryN(i)->getCoordinates().release();
        geos::geom::CoordinateSequence *newLonLatPts = new geos::geom::CoordinateSequence();
        // fix the points
 
        for (size_t k = 0; k < pts3->getSize() ; k++) {
          double lon = pts3->getAt(k).x;
          double lat = pts3->getAt(k).y;
          if (negAdjust) {
            lon = lon + 360;
          }
          else {
            lon = lon - 360;
          }
          newLonLatPts->add(geos::geom::Coordinate(lon, lat), k);
 
        }
        // Add the points to polys
        finalpolys->push_back(globalFactory->createPolygon
                              (globalFactory->createLinearRing(*newLonLatPts)).release());
      }
 
      // This loop is over polygons that will always be in 0-360 space no need to convert
      for (unsigned int i = 0; i < convertPoly2->getNumGeometries(); i++) {
        newGeom = (convertPoly2->getGeometryN(i))->clone().release();
        finalpolys->push_back(newGeom);
      }
 
      p_polygons = globalFactory->createMultiPolygon(*finalpolys).release();
 
      delete newLonLatPts;
      delete pts;
      delete pts2;
    }
    catch(geos::util::IllegalArgumentException *geosIll) {
      std::string msg = "Unable to create image footprint (Fix360Poly) due to ";
      msg += "geos illegal argument [" + IString(geosIll->what()) + "]";
      delete geosIll;
      throw IException(IException::Unknown, msg, _FILEINFO_);
    }
    catch(geos::util::GEOSException *geosExc) {
      std::string msg = "Unable to create image footprint (Fix360Poly) due to ";
      msg += "geos exception [" + IString(geosExc->what()) + "]";
      delete geosExc;
      throw IException(IException::Unknown, msg, _FILEINFO_);
    }
    catch(IException &e) {
      std::string msg = "Unable to create image footprint (Fix360Poly) due to ";
      msg += "isis operation exception [" + IString(e.what()) + "]";
      throw IException(e, IException::Unknown, msg, _FILEINFO_);
    }
    catch(std::exception &e) {
      std::string msg = "Caught std::exception: ";
      msg += e.what();
      throw IException(IException::Unknown, msg, _FILEINFO_); 
    }
    catch(...) {
      std::string msg = "Unable to create image footprint (Fix360Poly) due to ";
      msg += "unknown exception";
      throw IException(IException::Unknown, msg, _FILEINFO_);
    }
  }
  void ImagePolygon::Fix360Poly() {…}
 

  Blob ImagePolygon::toBlob() const {
    // Check to see p_polygons is valid data
    if (!p_polygons) {
      string msg = "Cannot write a NULL polygon!";
      throw IException(IException::Programmer, msg, _FILEINFO_);
    }
    
    geos::io::WKTWriter *wkt = new geos::io::WKTWriter();
    wkt->setTrim(true);
 
    string polyStr = wkt->write(p_polygons);
    delete wkt;
 
    Blob newBlob("Footprint", "Polygon");
    newBlob.setData(polyStr.c_str(), polyStr.size());
    return newBlob;
  }
  Blob ImagePolygon::toBlob() const  {…}
 

  double ImagePolygon::DistanceSquared(const geos::geom::Coordinate *p1, const geos::geom::Coordinate *p2) {
    return ((p2->x - p1->x) * (p2->x - p1->x)) + ((p2->y - p1->y) * (p2->y - p1->y));
  }
  double ImagePolygon::DistanceSquared(const geos::geom::Coordinate *p1, const geos::geom::Coordinate *p2) {…}
 

  bool ImagePolygon::IsLimb() {
    bool hasFourCorners = true;
    hasFourCorners &= SetImage(1, 1);
    hasFourCorners &= SetImage(p_cubeSamps, 1);
    hasFourCorners &= SetImage(p_cubeSamps, p_cubeLines);
    hasFourCorners &= SetImage(1, p_cubeLines);
    return !hasFourCorners;
  }
  bool ImagePolygon::IsLimb() {…}
 
 

  geos::geom::Coordinate ImagePolygon::FindBestPoint(geos::geom::Coordinate *currentPoint,
      geos::geom::Coordinate newPoint,
      geos::geom::Coordinate lastPoint) {
    geos::geom::Coordinate result = newPoint;
    // Use a binary search to snap to the limb when needed
    if (p_sampinc > 1  ||  p_lineinc > 1) {
 
      // Pull the invalid point back inside the image
      double x = lastPoint.x;
      double y = lastPoint.y;
      if (x < p_cubeStartSamp) {
        x = p_cubeStartSamp;
      }
      else if (x > p_cubeSamps) {
        x = p_cubeSamps;
      }
      if (y < p_cubeStartLine) {
        y = p_cubeStartLine;
      }
      else if (y > p_cubeLines) {
        y = p_cubeLines;
      }
      geos::geom::Coordinate invalid(x, y);
      geos::geom::Coordinate valid(result.x, result.y);
 
      // Find the best valid Coordinate
      while (!SetImage(invalid.x, invalid.y)) {
        int x, y;
        if (invalid.x > valid.x) {
          x = (int)invalid.x - 1;
        }
        else if (invalid.x < valid.x) {
          x = (int)invalid.x + 1;
        }
        else {
          x = (int)invalid.x;
        }
        if (invalid.y > valid.y) {
          y = (int)invalid.y - 1;
        }
        else if (invalid.y < valid.y) {
          y = (int)invalid.y + 1;
        }
        else {
          y = (int)invalid.y;
        }
        invalid = geos::geom::Coordinate(x, y);
      }
 
      result = FixCornerSkip(currentPoint, invalid);
    }
 
    return result;
  }
  geos::geom::Coordinate ImagePolygon::FindBestPoint(geos::geom::Coordinate *currentPoint, {…}
 

  geos::geom::Coordinate ImagePolygon::FixCornerSkip(geos::geom::Coordinate *currentPoint,
      geos::geom::Coordinate newPoint) {
    geos::geom::Coordinate originalPoint = newPoint;
    geos::geom::Coordinate modPoint = newPoint;
 
    // Step Too big
    if (p_sampinc > p_cubeSamps || p_lineinc > p_cubeLines) {
      return newPoint;
    }
 
    // An upper left corner
    else if (currentPoint->x < newPoint.x && currentPoint->y > newPoint.y) {
      while (newPoint.x >= currentPoint->x && SetImage(newPoint.x, newPoint.y)) {
        modPoint = newPoint;
        newPoint.x -= 1;
      }
    }
 
    // An upper right corner
    else if (currentPoint->y < newPoint.y && currentPoint->x < newPoint.x) {
      while (newPoint.y >= currentPoint->y && SetImage(newPoint.x, newPoint.y)) {
        modPoint = newPoint;
        newPoint.y -= 1;
      }
    }
 
    // An lower right corner
    else if (currentPoint->x > newPoint.x && currentPoint->y < newPoint.y) {
      while (newPoint.x <= currentPoint->x && SetImage(newPoint.x, newPoint.y)) {
        modPoint = newPoint;
        newPoint.x += 1;
      }
    }
 
    // An lower left corner
    else if (currentPoint->y > newPoint.y && currentPoint->x > newPoint.x) {
      while (newPoint.y <= currentPoint->y && SetImage(newPoint.x, newPoint.y)) {
        modPoint = newPoint;
        newPoint.y += 1;
      }
    }
 
    if (currentPoint->x == modPoint.x && currentPoint->y == modPoint.y) {
      return originalPoint;
    }
    return modPoint;
  }
  geos::geom::Coordinate ImagePolygon::FixCornerSkip(geos::geom::Coordinate *currentPoint, {…}
 

  void ImagePolygon::FindSubpixel(std::vector<geos::geom::Coordinate> & points) {
    if (p_subpixelAccuracy > 0) {
 
      // Fix the polygon with subpixel accuracy
      geos::geom::Coordinate old = points.at(0);
      bool didStartingPoint = false;
      for (unsigned int pt = 1; !didStartingPoint; pt ++) {
        if (pt >= points.size() - 1) {
          pt = 0;
          didStartingPoint = true;
        }
 
        // Binary Coordinate Search
        double maxStep = std::max(p_sampinc, p_lineinc);
        double stepY = (old.x - points.at(pt + 1).x) / maxStep;
        double stepX = (points.at(pt + 1).y - old.y) / maxStep;
 
        geos::geom::Coordinate valid = points.at(pt);
        geos::geom::Coordinate invalid(valid.x + stepX, valid.y + stepY);
 
        for (int itt = 0; itt < p_subpixelAccuracy; itt ++) {
          geos::geom::Coordinate half((valid.x + invalid.x) / 2.0, (valid.y + invalid.y) / 2.0);
          if (SetImage(half.x, half.y)  &&  InsideImage(half.x, half.y)) {
            valid = half;
          }
          else {
            invalid = half;
          }
        }
 
        old = points.at(pt);
 
        // Set new coordinate
        points[pt] = valid;
 
      }
 
      // Fix starting point
      points[points.size()-1] = geos::geom::Coordinate(points[0].x, points[0].y);
 
    }
  }
  void ImagePolygon::FindSubpixel(std::vector<geos::geom::Coordinate> & points) {…}
 
 
} // end namespace isis