I have two sets of 2d-data points which can be transformed in each other by using a certain transformation function (see also [this question][1]). The problem is that in both data sets there are points which do not have associated points in the other list. data1 = { {33.9168, 631.006}, {48.8067, 673.198}, {3.59394, 671.167}, {64.1931, 632.506}, {58.7559, 613.401}, {5.45129, 635.602}, {40, 500}, {55.6619, 651.298}, {40, 850}, {18.1513, 671.949}, {54.6781, 598.251}, {23.5348, 608.289}, {65.0549, 531.442}, {74.4132, 479.425}, {32.9808, 671.931}, {46.4516, 750.192}, {26.9262, 650.35}, {27.1816, 413.334}, {20.3858, 633.391}, {50.9284, 770.49}, {64.1628, 670.801}, {13.1805, 652.588}, {41.4876, 650.752}, {82.9996, 514.631}, {36.0045, 612.007}, {26.4914, 548.723}, {58.3295, 458.015}, {21.557, 801.607}, {5.84689, 800.425} }; data2 = { {1532.93, 536.587}, {1514.13, 789.}, {1530.22, 596.423}, {1520.66, 640.844}, {1540.5, 660.237}, {1530.03, 790.2}, {1559.17, 758.9}, {1556.15, 661.154}, {1580.39, 467.111}, {1525.63, 660.167}, {1571.44, 620.556}, {1512.62, 623.985}, {1520, 500}, {1533.79, 638.607}, {1526.88, 621.69}, {1560.9, 586.053}, {1572.13, 658.656}, {1548.37, 638.933}, {1532.8, 400.935}, {1540.44, 618.794}, {1590.15, 501.882}, {1554.5, 738.5}, {1564.73, 445.615}, {1543.06, 600.093}, {1565.69, 601.532}, {1562.55, 639.132}, {1511.34, 659.395}, {1580, 400}, {1585, 700}, {1571.9, 519.25} }; [![enter image description here][2]][2] In the upper plots I have marked these particular points. > **I have two questions** > > 1. How can I remove these marked non-associated points? > > 2. How can I sort the remaining points (in `data1corrected` and `data2corrected`, see below) in such a way that the first point of > `data1corrected` is corresponding to the first point `data2corrected` > and so on. For question 1 I think I should calculate all the point-distances of `data1` and then separately of `data2`. I expect it should be possible to find from this distances-information the additional anomalous points and remove them. For question 2 I have no idea. I wish then to receive e.g. for the corrected lists: data1corrected= { {21.557, 801.607}, {5.84689, 800.425}, {50.9284, 770.49}, {46.4516, 750.192}, {32.9808, 671.931}, {48.8067, 673.198}, {3.59394, 671.167}, {18.1513, 671.949}, {64.1628, 670.801}, {13.1805, 652.588}, {55.6619, 651.298}, {26.9262, 650.35}, {41.4876, 650.752}, {5.45129, 635.602}, {20.3858, 633.391}, {64.1931, 632.506}, {33.9168, 631.006}, {58.7559, 613.401}, {36.0045, 612.007}, {23.5348, 608.289}, {54.6781, 598.251}, {26.4914, 548.723}, {65.0549, 531.442}, {82.9996, 514.631}, {74.4132, 479.425}, {58.3295, 458.015}, {27.1816, 413.334} }; data2corrected= { {1530.03, 790.2}, {1514.13, 789.}, {1559.17, 758.9}, {1554.5, 738.5}, {1540.5, 660.237}, {1556.15, 661.154}, {1511.34, 659.395}, {1525.63, 660.167}, {1572.13, 658.656}, {1520.66, 640.844}, {1562.55, 639.132}, {1533.79, 638.607}, {1548.37, 638.933}, {1512.62, 623.985}, {1526.88, 621.69}, {1571.44, 620.556}, {1540.44, 618.794}, {1565.69, 601.532}, {1543.06, 600.093}, {1530.22, 596.423}, {1560.9, 586.053}, {1532.93, 536.587}, {1571.9, 519.25}, {1590.15, 501.882}, {1580.39, 467.111}, {1564.73, 445.615}, {1532.8, 400.935} }; [![enter image description here][3]][3] **The distance from each point to another point of `data1corrected` is aproximately the same as for the points of `data2corrected`.** [1]: https://mathematica.stackexchange.com/questions/189124/fitting-of-2d-data-points-with-a-function-considering-scaling-rotation-and-tran [2]: https://i.sstatic.net/DwcQa.jpg [3]: https://i.sstatic.net/BP1Zg.jpg [4]: https://i.sstatic.net/DPKfb.jpg