Pitney Bowes MapInfo Vertical Mapper - Manual (Page 137)

Chapter 7: Using Grids for Spatial Analysis
User Guide
135
• The Surface Elevation value is the elevation value found at the sampled location. All values are
based on the “no earth curvature” model, and they are not displayed in the graph window.
• The Relative Viewable Elevation value is the elevation at the sampled location that can be
seen from the viewing point. All values are based on the selected earth curvature model and are
represented by the green line in the graph window.
• The Relative Elevation value is the elevation value found at the sampled location. All values are
based on the selected earth curvature model and are represented by the red line in the graph
window.
If the No Earth Curvature model is chosen, then the Viewable Elevation and the Relative Viewable
Elevation columns will be the same. Also, the Surface Elevation and the Relative Elevation will be
the same.
The Plot on Map check box enables you to view a line plot in the Map window after clicking the
Solve button.
The line plot traces the extent of the line of sight and indicates, using colour, the intervals between
the endpoints that are visible (green) and obstructed (red) relative to the direction of sight. Line plots
are saved as individual MapInfo .tab files using default file names (subdirVMLineX.tab). As
subsequent lines are chosen and solved, new files are saved with incremental numbers in the file
name.
The Solve button enables you to initiate the point-to-point calculation.
The point-to-point visibility line
Exploring the Point-to-Point Solution Dialog Box
The Point-to-Point Solution dialog box is a graphical representation of the line-of-sight calculation.
Two lines of cross section are constructed in the graph window along the line of visibility.