I'm up to learning some COGO routines, using SurvCE rather than doing manually (which I'm familiar with). I gave up trying to do it with the software in the instrument itself.
But upon carefully reading the description of "Point to Line Measurement", I find that it's objective is to FIND the coordinates of the station upon which the instrument is set, based on two known points on a line.
I want the reverse. I know the coordinates of the instrument (and the two ends of the line, neither of which is visible (for this exercise) from the To Be Determined point ON said line.
So I don't think this is a "Point to Line" problem. I've looked through SurvCE "Intersections" and "Point Projections but am not seeing the relevant procedures.
What I'm really trying to do is to "Stake out" a point that will be on the line, and perpendicular to the line from the instrument (although my next objective will be to stake out additional points on the line NOT perpendicular to the line to the instrument.
Can anyone point me to the section in the SurvCE software I should be looking at? Here's the picture: (Instrument is at x3, y3)
You want Stake Line/Arc on the Survey Tab. 
Pick Define Line
Input the end points of the line
Select the Point On Line tab and chose Find Intersect to Line or Find Perpendicular to Line
Opps, I re-read the question and realized I posted bad info.
Under Cogo, chose Point Projection, Define Line, Enter the end points of the line, Then in the next screen input the point number of the instrument, below the input line you have options to stake, store, etc.
> Opps, I re-read the question and realized I posted bad info.
>
> Under Cogo, chose Point Projection, Define Line, Enter the end points of the line, Then in the next screen input the point number of the instrument, below the input line you have options to stake, store, etc.
Thank you. Never seen that screen, lol. I'm a bit confused about the info at the bottom of the screen ("Station: -48+92.607...Offset R1215.175"), but it seems to have done exactly what I was looking for. It looks like it's treating the line between the two known points as a centerline, then finding the distance along, and distance to the Right (in this case) of the setup point. That sound right?
It measures the stationing from the first point to the second point. A negative station indicates that the intersection point falls beyond point 1. A positive station greater than the length of Line 1-2 would indicate that the intersection point falls beyond point 2
>
>
> It measures the stationing from the first point to the second point. A negative station indicates that the intersection point falls beyond point 1. A positive station greater than the length of Line 1-2 would indicate that the intersection point falls beyond point 2
Got it! I had the wrong point in there. When I put the point number that was created ON the line, I get STA 11+18.458 with an Offset of L0.000, which I read as being 1118.458' from the first point, and ON the line.
I'll do a few more until it all makes sense. Thanks again.
I really don't understand what you are asking but here it goes.
Go to the Map screen and draw a line from point to point then draw a line from instrument and pick the perpendicular icon and select the first line. Or you can just inverse from instrument point to perpendicular to first line.
In the Define Line screen, there's a field toward the bottom that allows you to specify the Start Station. For point to line intersections Start Sta: should be set to 0+00.00 else it will give you misleading information as to the distance between the start point and the intersection point.
You can check the values by using these formulas:
Oops. I re-read your original post and see that you already know this. Sorry.
> Oops. I re-read your original post and see that you already know this. Sorry.
Apology not required. I actually like the compact version of the formula. I've been doing it in steps and manage to confuse myself (in addition to just plain pushing the wrong buttons on my HP), as often as not, doing it manually. Using a Data Collector, I'll be stepping into the 21st century (well almost).:-D
> You want Stake Line/Arc on the Survey Tab.
>
> Select the Point On Line tab and chose Find Intersect to Line or Find Perpendicular to Line
>
I finally tried "Find Perpendicular to Line" and it was completely successful until I tried to stake the point on the line behind an 18" hemlock.:-/
Do I understand correctly that if I chose, instead "Find Intersect to Line", I could swing to an angle other than perpendicular and then move out or in on that azimuth until on the line?
All that setting changes is how the software reports the offsets to the line. Here's an excerpt from the SurvCE 4.0 Manual:
"Stakeout by Define Line also has a Point On Line tab that enables, in total station
mode, staking of the intersect with the specified line on the current line-of-sight.
This is often used to set stakes or flagging along a property line by sighting gaps
in tree lines. The surveyor finds a gap in the line, takes a reading to the prism and
is advised how far to Move In or Move Out to stake the line at the current
line-of-sight. The Point on Line tab also includes the standard perpendicular
method, where any measurement is used to compute the direction and distance to
move to go to the point on the line perpendicular to the measured point."