A contour is drawn as polyline which consists of a series of
connected points with a
constant elevation. 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 calculations, but using sketch mode to digitize the
curved parts because it is fast and accurate.
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 program 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.
To digitize with a mouse instead of a digiting tablet, go to the
Settings menu, Configure, and General Settings. In the General
Settings dialog box, under Digitizer Settings, clear the check box for
Auto Tablet On For Digitize Commands.
This is the Digitize Contours dialog box.
Pulldown Menu Location: Surface > Digitize Contours
Keyboard Command: digcont
Prerequisite: Calibrate the tablet with the
Tablet Calibrate menu option if contours are to be taken
off an existing drawing.
File Names: \lsp\digcont.lsp, \lsp\contour4.arx