**7.1 Valid data**

The assessment process is made in two phases. The first is the visual checking and the second the parameters checking. According to the supervising team, at the end of this phase, data is valid when minimum criteria are met:


The tracking of the geologist attests his movement towards the point planned to be sampled.

If a point does not respect the above criteria (**Figure 17**), an investigation is made in order to invalidate it effectively or not. Thus, the GIS is checked again to understand if the river has not shifted or if the targeted one does not exist. The database is assessed to understand the comments of the geologist.

**Case A**: Valid data after visual checking on the GIS. Tracks prove that the geologist effectively reach the targeted planned points. But he did not found the stream at that place. One of the reasons is that the river shifted at the left. So he came back where the stream crossed to sample. In that case, all the minimum criteria contained in the SOP (Standard operation procedures) are met.

**Case B**: Invalid data after visual checking on the GIS. Tracks prove that the geologist did not reach the targeted stream, or the targeted point. And the distance between
