Deformation analysis between epoch 1+2+..k-1 vs epoch k

Hello Michael,

I'm just wondering that, Is JAG 3D software do the deformation analysis between epoch 1+2+3+...k-1 and epoch k.

Thank you.

Hello,

I'm just wondering that, Is JAG 3D software do the deformation analysis between epoch 1+2+3+...k-1 and epoch k.

JAG3D supports a comparison of two epochs. Usually, the current control epoch k is compared to the reference epoch and - sometimes - to the last control epoch k-1. In most cases, there is no further benefit to compare the e.g. epoch e=2 and e=6, if the current epoch is k=20. If you like to compare all epochs e=1...k-1 to k, you are able to combine the fist epochs, i.e. combine the data of {1...k-1} and carry out the congruence analysis to k. For an individual comparison, i.e. 1 vs. k; 2 vs. k; 3 vs. k; ... k-1 vs. k, you have to create individual projects (or enable/disable the needed/unneeded observation and point groups in a single project).

kind regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Tags:
deformation analysis, multi-epochs

Thanks alot. For my project, after the deformation analysis,

- for 1 vs k-1, displacement of a object point is x(mm)< alowwable maximum displacement for the object point.
- k-1 vs k, there are no displacement of this object point. The displacement of the object point is y (mm), y(mm) < ellipse error.
- but 1 vs k, displacement of the object point is z (mm). z(mm) > alowwable maximum displacement for the object point.

I'm just thinking about the reliability meaning of z (mm). Is the reality of z(mm) > alowwable maximum displacement for the object point.

Regards,

Hello,

I'm just thinking about the reliability meaning of z (mm). Is the reality of z(mm) > alowwable maximum displacement for the object point.

The reliability of the estimated coordinate components is derived by the observations and the stochastic model and depends on you network configuration. The shift or displacement of an object point can be simple verified. An object point should be defined twice in the JAG3D project, i.e. one-times per epoch. Thus, the shift is estimated by subtracting the values from each other. The related uncertainties of the shift-parameters are derived by applying the propagation of uncertainties.

kind regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Thank you so much

I think the stategy of the deformation analysis between k-1 and k to detect the stable or unstable of reference points in the network. Is that right?

Hello,

I think the stategy of the deformation analysis between k-1 and k to detect the stable or unstable of reference points in the network. Is that right?

Yes, JAG3D checks the reference points of the network by comparing the estimated test statistic and a given threshold (derived from the F-distribution). In case of an unstable reference point, the reference point should parametrierend as an object point (as already mentioned: in this case, the point should be defined twice, i.e. one-times per epoch).

regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Hello,

I'm just wondering that how to detect a movement of the block of reference points if this block really is moved.

Thank you.

Hello,

I'm just wondering that how to detect a movement of the block of reference points if this block really is moved.

A reference point is assumed to be stable. If this property cannot fulfilled by a point, this point isn't a reference point. Therefore, it makes no sense to check reference points for block shifts but - in some cases - it makes sense to detect the block moving of (unstable) object points.

regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

"A reference point is assumed to be stable point".

This point is input to JAG 3D as reference point or stochatic point. When I input it as datum point, JAG 3D doesn't work.

Hello,

"A reference point is assumed to be stable point".

This point is input to JAG 3D as reference point or stochatic point. When I input it as datum point, JAG 3D doesn't work.

The congruence analysis module of JAG3D bases on (a combined) free network adjustment. Therefore, only datum- and new points are valid. Thus, all the points, that are assumed to be stable reference points, should imported to a "datum point" group. Points, that are unstable or assumed to be unstable, are "new points".

(In congruence analysis, no stochastic or reference point group may exist. I'm sorry for the ambiguity of the term reference point. My fault!)

kind regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Could Form Fitting tool box detect the movement of the block of reference points when compare coordinates from the free adjustment of epoch 0 and epoch k?

Thank you

Hi,

I create an example to avoid misunderstandings. I prepare the data from the test network Delft, which is used in many investigation in the framework of congruence analysis, e.g. Niemeier 2008, Velsink 2015, Lösler et al. 2017 or Lehmann & Lösler 2017. The example contains a block-shift analysis for the east part of the network w.r.t. to the west part.

Download: Delft-project in JAG3D

kind regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Thank you so much. Your example help me too much. But my project, all of reference points outside the dam and object points on the dam are moved vs epoch 0. I want to detect the shifts of the block vs epoch 0.

Thank you.

Hello,

But my project, all of reference points outside the dam and object points on the dam are moved vs epoch 0. I want to detect the shifts of the block vs epoch 0.

If all reference points are shifted in the same direction and order of magnitude, the differences between the centroid of the reference points of epoch 0 and the centroid of the reference points of epoch k describes the shift parameters.

To proof that all reference points are shifted in the same direction and order of magnitude, you have to compare the internal configurations/geometries of the network in both epochs. This can be done by JAG3D in a normal congruence analysis.

/Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Hello,

What do A and C in the report mean? Are they ellipse error, aren't they?

A: semi-major
C: semi-minor

depending on the input of uncertainty of observations.

Thank you

Hello,

What do A and C in the report mean? Are they ellipse error, aren't they?

A, B and C are the confidences of the point, i.e. the major, middle and minor axis, respectively. Depending on the network dimension, B and C are not shown.

regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Thank you.

Assume that, in a monitoring network for concrete dam, accuracy requirement for the structure target points (95%RMS) is 5mm->standard deviation of all target points at each epoch must equal or smaller than 2.2mm.

Therefore, when designing the network in JAG3D, "A" is equal or smaller than 2.2mm, is that right?

One question, assume using Leica TC-2003 with angle standard deviation of this instrument is 0.5'', distance standard deviation is 1+1ppm. With angle is observed 24, distance is observed 24. What are uncertainty of angle and distance input to JAG3D? 0.5/sqrt/(24), (1+1ppm)/sqrt(24).

Hello,

Therefore, when designing the network in JAG3D, "A" is equal or smaller than 2.2mm, is that right?

The major-axis A depends on your selected α (and on the adjustment scheme of α to avoid multiple comparisons problem, i.e Baarda's B-method). The used α is given in the test-statistic table of JAG3D.

What are uncertainty of angle and distance input to JAG3D?

24 observations to the same point, observed from the same stand point???

If we observe several sets, we average the sets and use the manufacturer's specifications to define the a-priori uncertainties. After the adjustment process, the uncertainties are evaluated by variance-component-estimations and, if necessary, adjusted.

kind regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Thank you so much for your support.

Are baseline components and covariance matrix of GNSS baseline (2D or 3D) input to JAG-3D obtained from results of baseline data processing?

How to input the full of covariance matrix to JAG-3D when adjustment?

When do network pre-analysis, how to input covariance matrix to JAG-3D using GNSS receivers with, for example, horizontal accuracy: 5mm+0.5ppm, vertical accuracy: 10mm+0.5ppm.

Hello,

how to input covariance matrix to JAG-3D using GNSS receivers with, for example, horizontal accuracy: 5mm+0.5ppm, vertical accuracy: 10mm+0.5ppm.

JAG3D doesn't support full variance-covariance matrices. You can define the uncertainties of the baseline component (i.e. the variance taken from the variance-covariance matrix) or a distance dependent uncertainty model, which is similar to the uncertainty model of distance-measurements. If the horizontal and the vertical components haven't equal uncertainties, you have to calculate the uncertainties by your suggestion e.g. 5mm+0.5ppm and 10mm+0.5ppm.

/Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Thank you so much,

How to input alpha=0.01 to JAG-3D for pre-analysis?

Hi,

How to input alpha=0.01 to JAG-3D for pre-analysis?

There is no different between a pre-analysis and a regular adjustment. You can define the test statistic in Main menu --> Property --> Test statistic.

regards
Micha

--
applied-geodesy.org - OpenSource Least-Squares Adjustment Software for Geodetic Sciences

Tags:
test statistic, alpha

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