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I have a line and a point layer. The points are on a line(spline) I want to know the coordinates of 50 meters ahead based on a specific point. And I want to know the coordinates of 50 meters in the rear. I want to enter two coordinates into a table of points.(I have hundreds of them!) I have to solve it with QGIS or arcmap Python, but I have not found a way

  1. I created a buffer based on a point and then clipped it.
  2. I got both ends of the clipline, but it is not the exact length.
  • Please, select one platform and add what have you done so far – aldo_tapia Feb 13 '18 at 11:32
  • would your line be a straight line or any kind of curve ? – snaileater Feb 13 '18 at 11:49
  • If your data is in a projected coordinate system, and the line is straight, then use trigonometry. Calculate the angle of the line using the end coordinates, use the angle and distances as input into polar coordinates, convert the result back to Euclidean coordinates. – GBG Feb 13 '18 at 16:40
  • for an ArcGIS solution, look at arcpy.positionAlongLine(distance) – klewis Feb 14 '18 at 1:43