Carlson SurvNet

[Terry Strickland]

I have a question about survnet for current users. I have a need to
adjust multiple legs in a project without relying on the raw data file.
I use Carlson Survey and SurvCE. Most of my jobs are based on GPS
static control points which have already been adjusted by least squares
in the processing software. I will often have multiple legs of open
traverses in a project instead of the typical polygon closed traverse.

I would like to be able to input traverse point numbers and sideshots
and hold to the GPS control points, which are almost always more
accurate than my traverse with a total station, and just do a simple
compass rule adjustment. I used to do this in eagle point, but I have
been unable to figure out a way to do it in Carlson Survey since it uses
the raw data file and only allows for a single traverse per file. Can I
do something similar to this with Survnet, or is there a method in
Survey or SurvCE?

I sometimes also do a non-conventional traverse, like starting at the
same point of a "rectangle", run half way around, and go back to the POB
and run the other half, throwing the error at the far point of the
project similar to the way the GLO did the public land surveys. Can
Survnet perform this type of adjustment, possibly with least squares?
We normally close better than 1:10,000, depending on the terrain and the
distance between the occupation points, but I would like to be able to
adjust without jumping through hoops and using a third party package
other than Carlson.
thanks,
terry strickland

[Dave Karoly, PLS]

Yes, SurvNet will do what you want.

You import your GPS control as coordinate points in an RW5 file with a CSE (Control Standard Error) record at the top. You put ! ! ! * in the boxes which will make your N E and Z fixed.

At the end of the point list you add a CSE record with * * * * which will revert the software back to the standard values you enter in the project settings.

Then your raw data file needs to be stripped of any coordinate records. I've only been using it a short time but it did a very good job of figuring out where my weird traverses belonged. TGO can't do what SurvNet was able to do. It'll least squares adjust your data and give you information about how good your data is.

You can adjust everything together simultaneously if you want. Usually GPS vectors come with pretty small standard errors so I think your snakey traverse through there would carry less weight but I'm still a little foggy on this.

[tstrickland]

Thanks, Dave,
I have been planning on learning SurvNet, just upgraded to Survey 2008. I watched the video on Survnet. It has came a long way even since my post in 2005. I had forgot about the post till you brought it to the top! I'm excited about the capability of Survnet, and looking forward to learning it.

I will try the CSE records. Usually I have post processed coords prior to doing total station work. From what I saw on the video, you can import the GPS vectors and adjust all of it together, but I haven't tried it yet. It looks pretty cool. It will take me a while to get a feel for realistic numbers for standard errors using my equipment and procedures.
thanks again,
terry

[Dave Karoly, PLS]

yeah I've tried it out.

It works real slick.

The text file based input has a DOS feel to it; kind of reminds me of HEC2 where all input goes in from a file.

Obviously raw data would go in as text files.

But it would be nice to be able to have a dialog to enter control points like most other windows based programs.

A hint on importing GPS vectors-use the tool which converts your vector format to a *.GPS file then use the *.GPS file for import. This seems to work better. I had a weird problem that I think stemmed from using a Trimble *.asc file for input instead of converting it to *.GPS first.

[jahco@aol.com]

Following up on this, I use Sokkia Spectrum Survey for processing my GPS vectors. It exports to .SDR, or .IOB format. It would appear these files contain the same info as a .GPS file.

Was wondering if anyone knew of a utility to convert one of these files to a vector file that SurvNet could import?

John

[jahco@aol.com]

Looking back at this old post and want to update in case someone else runs into this.

The Sokkia Survey Spectrum software will export the vectors in an IOB format which is actually a Geolab file. Survnet will import a Geolab file with no problems or you can convert the IOB file to a survnet GPS file. Then the vectors are included.

John

[Gibbo]

Thanks for the tip John.