add tool tips
Added Tool Tips:
Samples a grid to estimate depth change
The distance between grid points. Smaller spacing results in more points. This results in more accurate estimation but slower run time.
Controls the search radius for the data points used in computing the z value of the grid point. Larger the radius, the more points used to compute z value. More points result in smoothing and slower runtimes. Too few points result in gaps in the estimation of change.