a =[20.7000000000000 0.940000000000000 0.285714285714286
20.3000000000000 1.14000000000000 0.400000000000000
20.3799305555556 1.69000000000000 0.209390189216075
20.3150000000000 2.69000000000000 0.146716623940051
20.4853333333333 3.69000000000000 0.109082911809985
20.5291666666667 4.64000000000000 0.0905936073059361
20.4428571428571 5.58285714285714 0.0752269779507133
20.4880952380952 6.66857142857143 0.0627798127798128
20.3211111111111 7.71777777777778 0.0516481760489431
20.5248333333333 8.69000000000000 0.0452567449956484
20.3939166666667 9.69000000000000 0.0387491043441037
20.4395833333333 10.6775000000000 0.0350519346031945
20.6222222222222 11.7288888888889 0.0296535525543159
20.1207142857143 12.4400000000000 0.0274903520141772
60.5666666666667 0.880000000000000 0.680000000000000
60.1000000000000 0.980000000000000 0.545454545454546
60.2000000000000 1.08000000000000 0.636363636363637
60 1.18000000000000 0.538461538461539
60.4791666666667 1.73000000000000 0.448534423994547
60.3301666666667 2.73000000000000 0.343515983241514
60.3648333333333 3.73000000000000 0.280795488275453
60.3830000000000 4.73000000000000 0.232835356768033
60.3762380952381 5.73000000000000 0.197759134956936
60.3897142857143 6.73000000000000 0.170902326844354
60.3943333333333 7.73000000000000 0.147946955922994
60.3035833333333 8.73000000000000 0.128683066670029
60.4251601731602 9.73000000000000 0.110998918780887
60.3042410714286 10.7675000000000 0.0960116354844498
60.2880000000000 11.7300000000000 0.0852706493745401
100.350000000000 0.920000000000000 0.628125000000000
100.500000000000 1.02000000000000 0.675000000000000
100.400000000000 1.12000000000000 0.594244604316547
100.900000000000 1.22000000000000 0.533333333333333
100.474814814815 1.74222222222222 0.505238883040056
100.377833333333 2.77000000000000 0.406211782079978
100.347833333333 3.77000000000000 0.340431720821620
100.443071428571 4.77000000000000 0.293370060763925
100.335383597884 5.72000000000000 0.256522949104151
100.429333333333 6.77000000000000 0.225453933210916
100.291063492064 7.77000000000000 0.199119961376308
100.404952380952 8.77000000000000 0.176846820076894
100.480012210012 9.73111111111111 0.155862112598764
100.381678571429 10.7700000000000 0.134376128508343
100.473666666667 11.5200000000000 0.125017593848161];
以上為試驗測得電機資料，第一列為轉速，第二列為轉矩，第三列為效率，請問如何繪制電機MAP圖。