Points
Under the points tab we can see all points (known and new) that are included in the adjustment. Known points are loaded automatically from the current polygon point file when we import a survey data file or enter survey data directly in the net adjustment. Both station (from) and object (to) points are checked.
It is also possible to change the coordinates of a known point manually, and to change points from known to new points if you want these to be calculated in the adjustment and not be used as fixed points (e.g. if you suspect that the known coordinates are wrong). A new point can be made known by entering the coordinates in the columns Known X, Y, or Z. To change this, go to the Known column, where you can also enter a point as known in plane but not in height or vice versa. If the coordinates for a point have been calculated, you can lock them by changing in the known column as mentioned previously. The calculated coordinates are then copied to the columns for known coordinates.
In addition to the coordinates, there are columns for centring errors X, Y, and Z. Here you can enter a centring error that you know applies to the point irrespective of the instrument. If we have blank cells here, the values we have entered for centring errors under Instruments will apply. For a normal tripod set up, 3mm is a normal error, but if we use wall prisms for example it is lower. A free station point always has the centring error 0, but its coordinates are usually of no interest.
We can also use the centring error if we use calculated points as known points from an old adjustment. Normally, all known points have a great accuracy, but by using the point mean errors from the old adjustment, we can provide observations in relation to worse known points with a little greater margin. As a result, uncertainty from these points (with greater mean errors from the old adjustment) will have less of an impact on our new adjustment.
Following the completion of the calculation we see Calculated X, Y, and Z, as well as Mean errors X, Y, and Z for the points, that tell us the calculated position of the new points and the precision they have. For a more detailed explanation for these headings, see Report.