Draw Outcrops

Function

Draw Outcrops generates polylines that represent the outcrops of strata from the selected drillholes. An outcrop is where a strata comes up to the surface. An option from the Outcrop Settings dialog allows the outcrop line to be calculated from where the top of the strata hits the surface or from where the bottom hits. The Draw Outcrop Polyline At Elevation will draw the outcrops as 3D polylines on the surface topography. For example, on a slope, the top of strata outcrop will be higher than the bottom, and on the inside when viewed in plan view. When coming from drillholes, Draw Outcrops calculates the outcrop by creating a grid of the surface and a grid for the strata and then finding the intersection of the two grids. If the strata never breaks through the surface, no outcrop line will be created. The Pre-Calculated model option reads the surface grid and strata grid from a pre-calculated grid file (.pre). This option will show a dialog with a list to choose from of the strata defined in the pre-calculated grid file. If the File option is used, then a Sub-Crop line can be drawn that will prompt for a thickness grid of the strata. The lines can be smoothed and vertices reduced with the settings shown below.