3.4.7View Traverse Solution

GrafNet computes a traverse solution automatically after processing each session. This feature can be used to view traverse solution files (TRV).

Traverse Solution

Once all of the baselines have been successfully processed, meaning that they are green in the Map Window, you will wish to produce coordinates for each of the stations. Accomplish this by using the traverse technique from known station to unknown stations. Using File | Add / remove Control Points, additional known (fixed) control points can be specified.

At least one GCP is needed per project before GrafNet will process any data, but others can be added later. These known control stations are used to transfer coordinates to unknown stations in the network.

In some ways, this is very similar to a conventional traverse survey but instead of instrument, backsight and foresight stations, this traverse technique only has an instrument and foresight station. Starting from the known stations, coordinates are transferred to the nearest stations. Then, the next nearest stations receive coordinates. This procedure is repeated until all connected stations have coordinates transferred. The arrow marker on the baseline shows which direction this transfer takes place.

The coordinates for a given station are transferred from the minimum number of legs. The lengths of the legs are not taken into account which, in some cases, results in an unfavorable transfer of position. In this case, the network adjustment produces more accurate coordinates.

For stations that have more than two baselines connecting, a loop tie can be computed. This means that there is more than one possible transfer of coordinates to this point. The first transfer is used for coordinate generation. Subsequent transfers are used to compute loop ties. The loop ties are good for locating erroneous baselines but they are an accumulated error of many baselines to that point. This means that the last baseline in that traverse leg may not be the erroneous one. These ties also give a good indication of the accuracy of the network, but the magnitude of the errors will be larger than the network adjustment residuals. The network adjustment method is not that much more accurate than the traverse method. Rather, the traverse method accumulates errors (closures) while the network adjustment spreads these errors across the whole network.