## Cogo Curves

**Moderators:** Brian Sloman, Jason Poitras, James Johnston

### Cogo Curves

So, I am determined to get the cogo batch program and Active editors figured out. I am entering in a 1957 road alignment traverse that is important to some boundary work that I am doing here. I want to use Batch cogo to do this rather than graphically. Using the dialog box for cogo curve; I fill in the point I want to start the curve from (502), I type in the points for my tangent (S34°E) and give it a minus 90 since the curve will be to the left (501..502-90). Then I fill in the radius point number and radius distance (503 and 520.8709). Step 3 I fill out the length of curve (257.34) give it a point number and description. Hit calc and walla! the program draws the curve clockwise to the NW instead of counterclockwise to the SE (tangent out should be S62°19'E). I am scratching my head on this and would really like some suggestions. Thanks for the help

### Re: Cogo Curves

By entering 501..502-90 you are telling the program that the instrument is on 502 backsighting a point that is on the same bearing as it is from 501 to 502 and then turning left 90 degrees. I if the back tangent bearing is S34E you enter 502..501-90 or if the ahead tangent is S34E then entering 501..502+90 will get you the proper results. The -90 really has nothing to do with whether the curve is left or right, rather which direction the radius point is from the line.