根据已知数据，最大值最小值和计划设定的等高线条数，获取最合适的，等高线分割和等高线条数；
采用缺省的，0.1，0.2，0.25，0.5的整数倍分割
1 /// <summary> 2 /// 计算等高线分割 3 /// </summary> 4 /// <param name="cormax">数据最大值</param> 5 /// <param name="cormin">数据最小值</param> 6 /// <param name="cornumber">计划设定等高线条数</param> 7 private void Standard(ref double cormax, ref double cormin, ref double cornumber) 8 { 9 double corstep, tmpstep, tmpnumber, temp, extranumber; 10 if (cormax <= cormin) 11 return; 12 corstep = (cormax - cormin) / cornumber; 13 if (Math.Pow(10, (int)(Math.Log(corstep) / Math.Log(10))) == corstep) 14 { 15 temp = Math.Pow(10, (int)(Math.Log(corstep) / Math.Log(10))); 16 } 17 else 18 { 19 temp = Math.Pow(10, ((int)(Math.Log(corstep) / Math.Log(10)) + 1)); 20 } 21 tmpstep = Math.Round(corstep / temp, 6); 22 //选取规范步长 23 if (tmpstep >= 0 && tmpstep <= 0.1) 24 { 25 tmpstep = 0.1; 26 } 27 else if (tmpstep >= 0.100001 && tmpstep <= 0.2) 28 { 29 tmpstep = 0.2; 30 } 31 else if (tmpstep >= 0.200001 && tmpstep <= 0.25) 32 { 33 tmpstep = 0.25; 34 } 35 else if (tmpstep >= 0.250001 && tmpstep <= 0.5) 36 { 37 tmpstep = 0.5; 38 } 39 else 40 { 41 tmpstep = 1; 42 } 43 tmpstep = tmpstep * temp; 44 if ((int)(cormin / tmpstep) != (cormin / tmpstep)) 45 { 46 if (cormin < 0) 47 { 48 cormin = (-1) * Math.Ceiling(Math.Abs(cormin / tmpstep)) * tmpstep; 49 } 50 else 51 { 52 cormin = (int)(Math.Abs(cormin / tmpstep)) * tmpstep; 53 } 54 55 } 56 if ((int)(cormax / tmpstep) != (cormax / tmpstep)) 57 { 58 cormax = (int)(cormax / tmpstep + 1) * tmpstep; 59 } 60 tmpnumber = (cormax - cormin) / tmpstep; 61 if (tmpnumber < cornumber) 62 { 63 extranumber = cornumber - tmpnumber; 64 tmpnumber = cornumber; 65 if (extranumber % 2 == 0) 66 { 67 cormax = cormax + tmpstep * (int)(extranumber / 2); 68 } 69 else 70 { 71 cormax = cormax + tmpstep * (int)(extranumber / 2 + 1); 72 } 73 cormin = cormin - tmpstep * (int)(extranumber / 2); 74 } 75 cornumber = tmpnumber; 76 }
采用数据间隔的下一位作为最小分割位，执行等高线分割操作
1 /// <summary> 2 /// 计算等高线分割 3 /// </summary> 4 /// <param name="cormax"></param> 5 /// <param name="cormin"></param> 6 /// <param name="cornumber"></param> 7 private void Standard2(ref double cormax, ref double cormin, ref int cornumber) 8 { 9 decimal max = (decimal)cormax; 10 if (cormax > 0) 11 { 12 double lmax = Math.Log10(cormax); 13 int fmax = (int)Math.Floor(lmax - 1); 14 double pmax = Math.Pow(10, fmax); 15 max = (decimal)Math.Ceiling(cormax / pmax) * (decimal)pmax; 16 } 17 else if (cormax < 0) 18 { 19 double lmax = Math.Log10(-cormax); 20 int fmax = (int)Math.Floor(lmax - 1); 21 double pmax = Math.Pow(10, fmax); 22 max = (decimal)Math.Floor(cormax / pmax) * (decimal)pmax; 23 } 24 double corstep = (cormax - cormin) / (cornumber - 1); 25 26 double lstep = Math.Log10(corstep); 27 int fstep = (int)Math.Floor(lstep - 1); 28 double pstep = Math.Pow(10, fstep); 29 decimal step = (decimal)Math.Ceiling(corstep / pstep) * (decimal)pstep; 30 31 decimal min = max - (step * cornumber); 32 cormax = (double)max; 33 cormin = (double)min; 34 }