Datum should be defined with Y1, X1 and Y2. How to perform that action?

Okay, this is an academical example. You want to fix the components of point `p1`

and one component of the point `p2`

. Thus, you have to define `p1`

as fixed reference point and `p2`

as stochastic point. Now, the trick is to fix the `Y2`

component of `p2`

by setting a height weight, i.e. a very small uncertainty, whereas `X2`

get a small weight, i.e. a large uncertainty.

Lets try an example taken from Benning (2007). It is a horizontal network containing four points, three sets of direction (in total 7 directions) and one distance group (in total 5 distances). Let us divide the points into two new points `p3`

and `p4`

, one reference point `p1`

and one stochastic point `p2`

.

**new_points_2d.txt**

3 0.0 0.0 4 1000.0 0.0

**reference_points_2d.txt**

1 0.0 1000.0

**stochastic_points_2d.txt**

2 1000.0 1000.0 0.00001 10000.0

The estimated coordinates are similar to the model, which defines the datum exactly by `Y1`

, `X1`

and `Y2`

. Anyway, this kind of datum definition is far away from practical use-case.

P.S. I guess this software works with

classical wayof defining datum parameters, am I right?

What does *classical way* means? JAG3D adjust a minimum constrain solution.

What about

min tragdefining of datum parameters?

I'm sorry. I'm not sure about the word *trag*. Can you explain the phrase *min trag*. Did you mean *min trace*? If yes, JAG3D minimises the trace of (a part of) the matrix `Qxx`

.

regards

Micha

Let me introduce you with my 'simple' student task...

I'm supposed to adjust 2d 4 point network with 12 measured directions and the same 12 measured distances.

Datum should be defined with Y1, X1 and Y2. How to perform that action?

From your previous message, I understood that I should store these 4 approximated points in the **new points**, am I right?

P.S. I guess this software works with *classical way* of defining datum parameters, am I right?

What about *min trag* defining of datum parameters?

Kind regards,

Milos

I did the first two steps you mention and also I imported approximated coordinates, but I don't understand what it means 'define point type' and how to do it.

JAG3D supports four kind of point types, i.e. new points, datum points, stochastic points and reference points. New points are points that haven't final coordinates. Datum points are also new points but these kind of points define your reference frame (geodetic datum) and are used to introduce some kind of (datum) restrictions, i.e. no network rotation or no network translation etc. Datum points are only valid in case of a so-called free network adjustment.

In some cases, you know the coordinates of some (reference) points. Due to the known coordinates, you don't want to estimate the coordinates of the reference points. Thus, you can import these points as stochastic points or (as fixed) reference points. Whereas a reference point is error-free, a stochastic point has some kind of uncertainties (e.g. a stochastic point is taken from a prior adjustment process).

how to set datum parameters

The free-network case:

In a levelling network, you need at least one datum point; (at least) two datum points are needed in a horizontal network; and (in most cases) three datums points are needed in the spatial case. This is the minimum constrain but you can increase the number of datum points. Beside the datum points, you can have several new points.

You don't have to set the datum parameters. Based on your datum points, JAG3D derives the datum conditions.

I noticed this software works with gons. Is there any possibility to convert it to degrees?

I'm sorry, the software supports only Gradian `2π = 360° = 400 gon`

because this is the traditional angle unit in Germany, Austria and Switzerland for geodetic engineers. Maybe a task for the next major release.

kind regards

Micha

First of all, I would like to thank you for your response. I was very happy this morning when I saw you respond. :) Are you a creator of this software?

I did the first two steps you mention and also I imported approximated coordinates, but I don't understand what it means 'define point type' and how to do it.

Could you tell me what reference, stochastic and new points are referring to and how to set datum parameters - e. g. point No1 defines datum. Should I import that point only in the datum points or it goes in the reference points too?

P.S. I noticed this software works with gons. Is there any possibility to convert it to degrees?

Hope I'm not bothering you a lot,

Milos

I couldn't find any tutorial in English.

Yes, you are right. As far as I know, there are no specific tutorials in other languages than German.

I want to adjust one network which data are collected by measuring distances, directions and angles. Could you tell me what concretely I should do?

A short introduction:

1. You have to create a **new project**

2. **Import** your raw files (e.g. distances, directions, etc.)

3. **Import** you approximated coordinates (e.g. from total station) and define the point type, e.g. datum points, new points etc.

4. Adapt the **stochastic model** (right click to the tree menu entry and select properties)

5. Run network **adjustment**

There are some sample files on sf.net e.g. the simple horizontal network from Baumann.

kind regards

Micha