A contour is a line of points with a
constant elevation, representing the natural contour of the site. In
Takeoff, there are two layer targets:
Existing
Ground Surface and
Design
Surface. Contour Polyline has two sub-command to digitize
contour lines
into Existing Contour and Final Contour layers directly for assigning
them
easily into Existing Ground Surface and Design Surface in the future
analysis.
There are two ways to digitize contour lines: sketch mode or point
mode. You can start digitizing a contour with one mode and switch to
the other during digitizing the contour. Sketch mode uses more points
than pick mode. In general, we recommend
using pick mode to digitize the straight parts of lines because it
reduces the number of points and
speeds up Takeoff's calculations, but using sketch mode to digitize the
curved parts because it is fast and accurate.
Function
This command lets you digitize
contours as polylines one at a time. The first time it prompts you the
Digitize Contours Dialog.
Enter
the layer name or select it from a list of
existing layer. Look at your plans and determine an elevation interval
that is
between most of the contours and enter it in the Elevation Interval
field. You are able to modify both the value and the direction of the
elevation
interval between digitizing contour lines, using the buttons on the
puck. To have Takeoff automatically close
contours whose beginning and ending points are within a specified
range, check the Auto Detect Close Contour. Draw Labels would
draw the elevation at the starting point of the contour. In Pick mode,
if you want the Takeoff to automatically zoom the display to center
around the last point when you get near the edge of the screen while
picking points, check the Auto Zoom Center. Click OK to start
digitizing.
If this is your first time digitizing a contour, you are defaulted to
the Pick Mode digitizing, otherwise you would be defaulted to the last
digitize mode. If you want to use the other digitize mode, press 0 on the puck or enter 0 from the keyboard.
Place
your cursor at one end of the contour line and begin digitizing
the line. While digitizing a line, you can force a contour to close on
itself by pressing A
on the
puck to end the contour and connect the
last point to the first point, remove a mistake by pressing B on the
puck, or switch to the other digitize mode by pressing 0. During Sketch
Mode
digitizing, you can stop digitizing by pressing
Pick or Enter button on the puck, take some rest or changes, and
start sketching again. At the end of the contour line, press
Enter on your puck or
keyboard. The contour is completed, and the elevation for the next
contour is automatically incremented. You would be asked to digitize
next contour. If you press A
on the puck or enter Yes
on
the keyboard,
you can digitize another contour, or press
B on the puck or enter
No
on
the keyboard to finish digitizing contours.
Have a
digitizer board and a puck connected to your computer, and have Wintab
driver installed. The digitizer has been correctly set up. Have done
tablet calibration for
current drawing.
Keyboard Command:
digcont_exist, digcont_final