
 Boxes at the top let you select the maximum lags to test, from
each point in a feature. These are in grid units. In
this case we know the migration should be to the NE, so the values
to the south and west are 0.
 All features: For each feature in the original grid, the
algorithm will attempt to find a corresponding point in the migrated
grid. The score will be the percentage of points that had a
match, with the largest percentage being the computed shift.
If several shifts have the same score, the computed shift will be
the centroid of the points with the tied score.
 Reverse (all): flips the original and migrated
grids, the box containing the lags to test, and the resulting lags.
This basically finds the motion that must be reversed to go from the
migrated feature to an original feature.
