GLG410--Computers in Geology

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GLG410 Excel warm up exercise: rotation computer

  1. Make little design in the spreadsheet by plotting the Original Coordinates of the corners (label them as Easting (E) and Northing (N)):
    1   1
    2   0
    1   -1
    -1  -1
    -2  0
    -1  1
    1   1
  2. Plot it as a XY Scatter and connect the dots
  3. Now we want to rotate the design.

    The coordinates are transformed by a rotation about the origin so that one axis is the distance along the profile and the other is the deviation from the plane of the profile. The equations for such a coordinate transformation are as follows:

    where E,N are the original coordinate system and E', N' are the rotated coordinate system, j is the rotation angle (should it be in radians or degrees? Note that Excel can only think in radians so you need to convert).
    Make a pair of columns called E' and N' (Rotated Coordinates) and use relative and absolute referencing or names to implement the equations.
  4. Add the new series of rotated data to the original plot and rotate the figure by changing j (phi). Which direction is the positive rotation direction?
  5. Now let's displace the data as well. Make two cells that are the delta_E and delta_N cells
  6. Make two new columns that use absolute referencing or names to add the displacements to the rotated coordinates (those would be the Rotated and displaced coordinates).
  7. Add the new series of displaced and rotated and displaced data to the original plot and displace the figure here and there by changing the delta_E and delta_N cells
  8. To get things to display nicer, set the axes to fixed ranges (right click on each axis and select format axis and change the axis options minimum and maximum)
Here is a demo of what I am basically looking for (note that I changed the shape from what I suggest above):

Turn in the nicely formatted and labeled spreadsheet and chart and answer the question above about the rotation direction.

GLG410 Computers in Geology

Last modified: September 1, 2011