# 2 distincts stations in one adjustement

Hello Micha,

Whereas a direction is a un-orientated observation, a direction angle is defined between a station and two target points. For that reason, a single direction makes not sens because it only contributes to the unknown orientation. However, if really all directions between the CD points are derived within the same datum, you can enable the group. In this case, all directions contribute to the same unknown orientation redundantly. As already mention, I was not sure about this fact and, therefore, disabled such pseudo-observations.

Indeed, all the directions are derived within the same datum. But in this case, I do not understand how JAG3D can calculate his network without enable the group. I thought that there should have a geometric problem : no complete link between CD points. Why JAG3D can calculate this group ?
I thought that we need vector 3D constant between couple of points, dX, dY, dZ. But we get the option to insert raw data with high level of precision. We insert it in JAG3D, with 3 differents kind of observations ; without directions sets, we lost an essential information in 2D.

Are you referring to the unknown orientation? This parameter describes the discrepancies of the north-direction of your frame and the zero-direction of the total-station (angle-encoder). See above, a direction is not an (direction) angle. A direction of 100 gon (90 °) does not imply that the target point is located in the east.

No I do not referring to the unknown orientation of the total station. We understand well this concept.
We are referring to insert an orientation between points to generate vector 3D or eccentricity to the CD points presents in our network

No, just averaging the coordinates in Excel, for instance, and reduce each coordinate by the mean. Currently, the network extent is about 500 m x 500 m. If, for example, the origin is set to 0/0, the maximal coordinate becomes 500/500. Small coordinate values will increase the numerical stability because of the 64 bit limit of double values --> https://en.wikipedia.org/wiki/Double-precision_floating-point_format.

Ok thanks you but this subject is ok.
But it is introduce a problem of our georefencement points. Today, we are in France and we used local EPSG (for exemple, 2154 in this worksite). But JAG3D adjustement do not consider the projection : we can not integrate this information in the metadata of one project. Is it right ? Or we don’t use correctly JAG3D ?
If not, it could be an usefull update.

Thanks,

Kind regards,
Antoine