cdm/src/main/java/ucar/nc2/dt/grid/GridCoordSys.java
@Override
  public int[] findXYindexFromCoord(double x_coord, double y_coord, int[] result) {
    if (result == null)
      result = new int[2];

    if ((horizXaxis instanceof CoordinateAxis1D) && (horizYaxis instanceof CoordinateAxis1D)) {
      result[0] = ((CoordinateAxis1D) horizXaxis).findCoordElement(x_coord);
      result[1] = ((CoordinateAxis1D) horizYaxis).findCoordElement(y_coord);
      return result;

    } else if ((horizXaxis instanceof CoordinateAxis2D) && (horizYaxis instanceof CoordinateAxis2D)) {
      if (g2d == null)
        g2d = new GridCoordinate2D((CoordinateAxis2D) horizYaxis, (CoordinateAxis2D) horizXaxis);
      int[] result2 = new int[2];
      boolean found = g2d.findCoordElement(y_coord, x_coord, result2);
      if (found) {
        result[0] = result2[1];
        result[1] = result2[0];
      } else {
        result[0] = -1;
        result[1] = -1;
      }
      return result;
    }

    // cant happen
    throw new IllegalStateException("GridCoordSystem.findXYindexFromCoord");
  }
@Override
  public int[] findXYindexFromCoord(double x_coord, double y_coord, int[] result) {
    if (result == null)
      result = new int[2];

    if ((horizXaxis instanceof CoordinateAxis1D) && (horizYaxis instanceof CoordinateAxis1D)) {
      result[0] = ((CoordinateAxis1D) horizXaxis).findCoordElement(x_coord);
      result[1] = ((CoordinateAxis1D) horizYaxis).findCoordElement(y_coord);
      return result;

    } else if ((horizXaxis instanceof CoordinateAxis2D) && (horizYaxis instanceof CoordinateAxis2D)) {
      if (g2d == null)
        g2d = new GridCoordinate2D((CoordinateAxis2D) horizYaxis, (CoordinateAxis2D) horizXaxis);
      int[] result2 = new int[2];
      boolean found = g2d.findCoordElement(y_coord, x_coord, result2);
      if (found) {
        result[0] = result2[1];
        result[1] = result2[0];
      } else {
        result[0] = -1;
        result[1] = -1;
      }
      return result;
    }

    // cant happen
    throw new IllegalStateException("GridCoordSystem.findXYindexFromCoord");
  }
Given a point in x,y coordinate space, find the x,y index in the coordinate system.

@param x_coord position in x coordinate space.
@param y_coord position in y coordinate space.
@param result  put result (x,y) index in here, may be null
@return int[2], 0=x,1=y indices in the coordinate system of the point. These will be -1 if out of range.