This step consists of entering information following the rules of each of the different tabbed pages.

- Spatial references

- Temporal references

- Depths

- Missions

- Areas

- Data types

- Keywords

The information that you enter allows the system to identify the data set that you are looking for. While you are building your query, you can check on the lower bar to see the number of data files that correspond to your current query specifications.

The information that you enter on the tabbed pages is linked by certain rules of logic. On a single page, the logical operator "OR" is applied to information on the different lines. For example, if a spatial reference is made up of two rectangles, then all the data falling within each of the rectangles will be included. This statement might seem trivial at first glance, but it is difficult to imagine a set of data that could belong to two non-overlapping rectangles simultaneously, which would be the case if the "AND" operator had been used. In practice, the possibility of including several criteria within a single page allows the creation of fairly complex queries. If not, it would be necessary to create and submit several independent queries to arrive at the same result.

The information provided on the different tabbed sheets is joined by the logical operator "AND." That means that the data set is the intercept of those that simultaneously meet the conditions of all the tabbed sheets. One must be careful not to specify criteria that will exclude all data; for example, if you specify a fixed station whose position falls outside of the rectangle on the spatial references page, then there would be no data fulfilling both these criteria.