坐标系统转换

2015-06-10 11:12:04 访问(2720) 赞(0) 踩(0)


		/// <summary>
		/// We use the Math.Round method since none of the transforms are exact.
		/// </summary>
		/// <param name="msg"></param>
		/// <param name="p1"></param>
		/// <param name="p2"></param>
		private void ComparePoints(string msg, DPoint p1, DPoint p2)
		{
			int prec = 5;
			if (Math.Round(p1.x, prec) == Math.Round(p2.x, prec) &&
				Math.Round(p1.y, prec) == Math.Round(p2.y, prec))
			{
				outputTextBox.AppendText(msg + " points are equal: (" + Math.Round(p1.x, prec) + ", " + Math.Round(p1.y, prec) + ") == (" + Math.Round(p2.x, prec) + ", " + Math.Round(p2.y, prec) + ")\n");
			}
			else 
			{
				outputTextBox.AppendText(msg + " points are NOT equal: (" + Math.Round(p1.x, prec) + ", " + Math.Round(p1.y, prec) + ") != (" + Math.Round(p2.x, prec) + ", " + Math.Round(p2.y, prec) + ")\n");
			}
		}

		/// <summary>
		/// We are going to use the CoordSys transform to transform a point from one coordsys to another then back
		/// again to see if the round trip produces the correct results. Then test the array version of the transform.
		/// </summary>
		private void UseCoordinateTransform()
		{
			// create LongLat projection
			CoordSys csys = Session.Current.CoordSysFactory.CreateFromPrjString("1, 56");
			// Create Robinson projection
			CoordSys csys1 = Session.Current.CoordSysFactory.CreateFromPrjString("12, 62, 7, 0");
			if (csys == csys1)
			{
				outputTextBox.AppendText("Oops, coordsys's are equal, this is bad\n");
			}
			CoordinateTransform coordTransform = Session.Current.CoordSysFactory.CreateCoordinateTransform(csys, csys1);
			DPoint pntSrc = new DPoint(0, 0);
			DPoint pntDest = coordTransform.CoordSys1ToCoordSys2(pntSrc);
			DPoint pntSrc1 = new DPoint(1, 1);
			DPoint pntDest1 = coordTransform.CoordSys1ToCoordSys2(pntSrc1);
			DPoint pntBackToSrc = coordTransform.CoordSys2ToCoordSys1(pntDest1);
			ComparePoints("Round trip", pntSrc1, pntBackToSrc);
			// compare the result with arrays
			DPoint[] pnt = new DPoint[2];
			pnt[0].x = 0;
			pnt[0].y = 0;
			pnt[1].x = 1;
			pnt[1].y = 1;
			coordTransform.CoordSys1ToCoordSys2(pnt, out pnt);
			ComparePoints("Array converted", pntDest, pnt[0]);
			ComparePoints("Array converted", pntDest1, pnt[1]);
		}


/*
Round trip points are equal: (1, 1) == (1, 1)
Array converted points are equal: (-185.01084, 1016.56978) == (-185.01084, 1016.56978)
Array converted points are equal: (94252.59365, 107958.96011) == (94252.59365, 107958.96011)
*/