Localization Help!

[Jim Frame]

Some months ago I did a localization that worked well as an aid to searching for monuments. I haven't tried the technique again until today, and this time I wasn't able to get it to work. I'm hoping someone smarter than me can tell me where I went wrong. Here's what I did:

1. I entered some approximate coordinates calculated from a record map and overlaid on a georeferenced image to produce rough SPC values (CA Zone 2).

2. I created a page named RECORD and imported the coordinates to it.

3. I created a page named CONTROL set up for SPC and located 4 of the monuments using my local RTN.

4. I created a localization by holding the 2 farthest monuments and using the 2 in between as checks:

4. I created a page named SEARCH set up to use the Local Yolo CS:

5. I tried staking out one of the monuments in the SEARCH page:

However, I missed it by the shift magnitude between coordinate systems.

Where'd I go wrong?

Thanks!

 

[Shawn Billings]

Because you imported the rough coordinates in a known coordinate system, the translation will not apply to them. They will simply be transformed. The geodetic relationship will remain unchanged. As you observed.

You have two options. First option was to import rough coordinates in unknown system. Down side is that you can't stake to unknown coordinates, so you can't use them to help find points. After localization the unknown system graduates to new local system, coordinates can then be staked.

Option 2, at the stage you're at now, re-import your rough coordinates as new local coordinates. Overwrite previous import. Now points are ready to stake.

 

[Jim Frame]

Option 1 doesn't sound very practical due to the lack of search value. Option 2 seems pretty clunky, as it requires a re-import. Is there really no smoother method?

 

[Matt Johnson]

Jim you could always use Shift and Rotate CoGo functions to translate your imported points.

 

[Jim Frame]

Jim you could always use Shift and Rotate CoGo functions to translate your imported points.

I don't think Shift was available -- and I'm sure Rotate wasn't -- the first time I localized, which is the reason I localized in the first place. I just tried it, and have some questions:

1. Since I only want to Shift/Rotate a subset of my Design points, I tried to specify a point range, but couldn't figure out how to do it. Selecting each point individually is a hassle, so I'm sure there's a better way.

2. The Rotate function appears to be looking for a rotation angle. Is there a way to indicate this by using point names, or do I have to calculate it and hand-enter it?

This seems like elementary cogo stuff, but I don't see anything about it in the LS manual. Is this material covered in a manual that I don't have?

Thanks!

 

[Nate The Surveyor]

Jim Go and look at my recent post:
Cogo Shift, or Translate

What you want is right there.
I often enter deeds, without knowing (or caring) about their geodetic location. With these tools, we should be able to accomplish things faster, and smoother.
The other day, I entered 47 coords, off an old survey. Left them on the thumb drive.
Set up, and localized on those. (fine, we finished the job that way)

BUT

If I had figured out COGO: Rotate, and "Shift" (see my bad nomenclature comment!), my job would fave gone better, faster, and easier!

Jim, I really like doing cogo in the field. sometimes rotating, and translating 4-5 times, just to "Look" at how it fits.

N

 

[Matt Johnson]

I don't think Shift was available -- and I'm sure Rotate wasn't -- the first time I localized, which is the reason I localized in the first place. I just tried it, and have some questions:

1. Since I only want to Shift/Rotate a subset of my Design points, I tried to specify a point range, but couldn't figure out how to do it. Selecting each point individually is a hassle, so I'm sure there's a better way.

2. The Rotate function appears to be looking for a rotation angle. Is there a way to indicate this by using point names, or do I have to calculate it and hand-enter it?

This seems like elementary cogo stuff, but I don't see anything about it in the LS manual. Is this material covered in a manual that I don't have?

Thanks!

These functions are new so aren't in manual you have but an updated manual will be released soon. You can specify a range of points using ".." in the search box. For example, "100..150", would find points 100 through 150. The help screen details the use of the filters and search box. You could also turn off the other pages to hide points from those pages.

To calculate the rotation angle or shift, use the

button. For Move and Shift it is looking for two points can calculated the difference between the second and first point selected so that it translates from the first point to the second point. For Rotate, it is looking for 2 points to calculate an angle with vertex PB. If will calculate the angle to rotate your points from the first point to the second point around PB.

 

[Nate The Surveyor]

Reporting a minor glitch in localize.
We had a traverse, 25 yrs ago!!) across a Section. We had good discipline, and it was pretty tight. But, as I retraced it, I tied into 7 points, (so far) and this exceeded the 6 point localize per page. So, it goes to page 2. Well, the page 1 and 2, at the bottom of the screen, cannot be seen, unless you hit the UP or DOWN arrow, to get it to show.
As I work, to refine this localization, the page(s) should show at all times. I want to set this job up, so that when I return, in 1 yr, or 5 yrs, I can tell what happened!
Thanks!
Nate

 

[Matt Johnson]

Reporting a minor glitch in localize.
We had a traverse, 25 yrs ago!!) across a Section. We had good discipline, and it was pretty tight. But, as I retraced it, I tied into 7 points, (so far) and this exceeded the 6 point localize per page. So, it goes to page 2. Well, the page 1 and 2, at the bottom of the screen, cannot be seen, unless you hit the UP or DOWN arrow, to get it to show.
As I work, to refine this localization, the page(s) should show at all times. I want to set this job up, so that when I return, in 1 yr, or 5 yrs, I can tell what happened!
Thanks!
Nate

Thanks, I confirmed this.

 

[Shawn Billings]

Option 1 doesn't sound very practical due to the lack of search value. Option 2 seems pretty clunky, as it requires a re-import. Is there really no smoother method?

Jim, we've worked out a smoother method that allows for searching and removes need to reimport. The trick is to create a duplicate of your State Plane Coordinate System and use Adjust Grid to Ground and Rename to change the name of this duplicate system. Leave all parameters at zero (translation, rotation, scale in ppm, etc.). Import your points. Go into the field and use the points in their approximate State Plane positions to find monuments in the field. After you find a couple of monuments that are well spaced, use localize. Set the Design coordinate system to your renamed State Plane System. When you store the localization parameters, the translation rotation and scale will update. As you find more points you can continue to localize, updating the localization parameters with each iteration. Pay attention to the scale factor. You can force the parameters to accept a manually entered scale factor (such as the combined factor) or let the Seven Parameter Transformation determine the scale factor from the comparison of the design points and your survey points. I typically prefer to manually enter the scale factor to match what I know the proper combined factor should be.

 

[Shawn Billings]

Jim,
Please see this video regarding localizations with coordinates with high relative accuracy and approximate global accuracy, such as geo-referencing precise total station surveys using geo-referenced aerial photogrammetry. I found this process works extremely well, iteratively improving the results of the localization with each added point. Also, by creating blank localization before importing the points, there is no need to re-import anything. This was done with a recent testing version. I believe it will also work with the existing release version, but I cannot say for certain.

The workflow is:

• Create new Project
• Create new Localization using the intended Coordinate System of the import points as the underlying "Surveyed" Coordinate System
• Create a Page with the Coordinate System set to the new Localization (currently all transformation parameters are null)
• Import approximate coordinates into New Page
• Navigate to first point, once recovered, collect a point
• Go to Localization, add new surveyed point and save Localization (populates translation parameters - recommended to use 3D-Horizontal/Vertical)
• Navigate to second point, once recovered, collect a point
• Return to Localization, add new surveyed point and save Localization (modifies translation parameters, adds rotation and scale - recommended to use 2D-Horizontal)
• Continue through remaining points, adding recovered surveyed points to localization.
• Watch residuals for outliers, switch from 2D to Check as necessary.
• Not discussed in the video is the ability to force the scale factor to the geodetic scale factor. This video uses the scale factor calculated from the Helmert transformation (based on comparative differences in the observation to the imported distances).

 

[Shawn Billings]

Note: the above process works for coordinates that are not geo-referenced also. The most significant difference is that you cannot use stake out to navigate to the first point. You will need to recover at least one monument to establish the translation. Depending on the accuracy of the bearing basis, you may need to recover a second monument to establish rotation as well before being able to use the coordinates for reconnaissance. However, once that is done, the localization can be refined iteratively as described in the video.

 

[Jim Frame]

This looks promising. I'll have to set aside some time to try it out.