Extending topo survey in SurvCE

> Just use existing job file with all existing points, so I can see were I need to fill in, re localize on the same point, check, and carry on? Perhaps I will degrade previous points? Choose option not to localize previously surveyed points?
After your first day you should have a correct (+/-, for your project) coordinate for the monument your base station is set up over. Use that base station coordinate for the second day's collection, and check into the "localization point".

Hi
Thanks for the reply.

We were advised by the supplier, a Licensed Cadastral Surveyor, to place the base at the most convenient location and set it going. It does record static data, but we have not needed to use it. Advantages of this are that we do not have an external radio, so range is limited, the base is place central to control points and or site, and best sky view, elevation.

We then use the rover to localize and check known points (average of ten observations), and then survey. If we have control points close enough with good Horizontal and Vertical and we confirm we are happy. Although in some cases a control can have excellent Horizontal position but no orthometric height, or an old bench Mark will have great vertical but poor horizontal position. Some we start with vertical for localization and adjust position if necessary.

Ntrip has not been used as we do not have good cell data coverage.

We tie our work to boundarys and do limited setout work, but with the disclaimer that we are surveying for engineering purposes only.

> A second question;
> I believe that you can use points from a previous job or "Control" job in SurvCE, can anyone provide directions to the procedure for this?

I'm absolutely not an expert (and didn't stay in a Holiday Inn Express last night either), but...
I did have to learn doing exactly this, albeit using total station data.

First you export all your points from the previous day as an ASCII file from whatever desktop software you're using, or from SurvCE.

Then, open a new job, choose "Import", "Import ASCII file".

Then click "select file", and choose "User defined" for file type, and "ASCII" from the drop down menu; click OK (green checkmark).

That brings you to the "destination file" screen, where you save it as a regular CRD file, called "control 18may15" or whatever.

When you open the new job, in "options", you check "Use Control File", and choose the CRD you just imported.

Voila: all your points are now in the new control file.
As always, any more seasoned folk who believe I've sent you astray, please chime in.

> I'm not familiar with the term "Licensed Cadastral Surveyor". Are you in the USA?

Hi Norman
No I'm in New Zealand.

Current title is Registered Professional Surveyor in New Zealand.

> The question is do I;
>
> Just use existing job file with all existing points, so I can see were I need to fill in, re localize on the same point, check, and carry on? Perhaps I will degrade previous points? Choose option not to localize previously surveyed points?
>

Since we use field to finish, even if I start a new job, I load the points I have already collected into SurvCE, and in the map screen run the field to finish routine. This allows me me to see the linework that is already existing, and then I proceed. Unfortunately, you do not see points from an assigned control file on screen with SurvCE.

The decision to use a new job and localizations is a little complex.

Raw data and localizations interact with each other in a dynamic way. If you reprocess the file with a new localization, please make sure that you know for certain what you are doing. I often save a backup file, or create a copy.

I am not aware of a way to assign a different localization to different parts of a raw data file for reprocessing. So, I would start a new file, and simply import the points that I want to see in on my screen.

Just generally your thinking should be to establish coordinates on a mark for your base station to set on. Then use those coordinates consistently for the life of the project. How you establish those coordinates depends on the resources at hand and the needs of the project. A field localization to establish control for a design project of even a minor public work is, perhaps, a bit crude for my liking. I'd prefer multiple vectors taken over a period of time and LS adjusted. But as long as you fix the coordinate once determined and stick with it, all should be well. As long as that base station monument remains fixed in place and unmolested.

Here in the US the agencies that traditionally established geodetic control coordinates on brass monuments have not been maintaining the network of points for quite a few years. Reliable brass is getting harder and harder to come by. We rely instead on the CORS (Continuously Operating Reference Stations) and OPUS. I know that there is AUSPOS in Australia, not sure if that covers NZ or not. Perhaps NZ has it's own version? If it does that is bound to be the go-to source for reliable positioning relative to the appropriate and current spatial reference frame.

With regard to setting your base - put it in a very open position. If you have to go a little further from your site to get a very open position that is better than putting it closer under a more obscured sky. Find a super open place within radio link range.