Spectra Precision FAST Survey Reference Manual User Manual
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2D Polyline (Road) :
This command allows you to draw a 2D Polyline. You can draw by point number, with ranges as in 8-12, or by picking
on the screen using snaps or picked points. This command is similar to the polyline command described above with the
following additions:
+/-:
The +/- options activate an additional prompt that allows you to plot line segments at a 90 degree
deflection angle from the last line. [+] is a right deflection and [–] is a left deflection.
Len
: This option prompts you for the length of a line segment. Enter the length and a line segment will be
drawn that length using the same bearing as the previous line segment. If the previous segment is an arc, then
the new segment will be tangent to that arc.
3D Polyline (3DP):
The 3D Polyline command is similar to the 2D polyline command. It will even draw arcs, but will create a polyline on
the screen with many vertices at different Z elevations which are linearly interpolated around the arc. If the start of the
arc is point 17 at elevation 842.246 and the end of the arc is point 9 at elevation 839, then using View, List, you would
see intermediate vertices (note that the segment length between vertices is about 0.12 units).
Using the snaps to draw lines can accomplish advanced coordinate geometry calculations. For example, if you offset two
polylines and wanted to determine the point where the offset lines intersect as well as the corner of the driveway, you
could draw a line from intersect to endpoint and do the command Polylines to Points (COGO, Create Points), which
would create points 50 and 51. Polylines to Points will not find intersects, so it is more direct to simply do Draw Locate
Points and use the intersect snap to create point 50 (COGO, Create Points). These procedures avoid complicated
COGO involving curve-line intersects at offset. If your goal is to stake out points, you do not even need to create Point
IDs, since the comand Stake Points will locate points by snap, directly from the drawing.