Map of the nine FLAMES fields of view observed with GES in the direction of L1688: blue open circles show the GIRAFFE targets, red dots represent the UVES targets, and green filled squares represent the GIRAFFE data collected from the ESO archive. Dotted lines outline 25 arcmin diameter fields of view. The orange star shows the median location of the star positions and the orange dashed line represents the northwest-southeast direction that is introduced in Sect. 4.3. The dashed box marks the location of the dense molecular cloud containing the pre-stellar cores.