Distribution of z ∼ 5.7 LBGs (top), z ∼ 5.7 LAEs (middle) and z ∼ 6 i′-dropouts (bottom) in the field J1030+0524 (left column) and J1137+3549 (right column). The size of each circle indicates the apparent magnitude bin with larger circles representing brighter magnitudes. The star symbol indicates the line of sight to the C iv systems. Masked areas of the field (bright Galactic stars and edges of the CCD) are shaded grey. The area is colour-coded according to the surface density contrast Σ/〈Σ〉 obtained using 1 h⁻¹ comoving Mpc bin size and a Gaussian smoothing kernel with FWHM of 10 h⁻¹ comoving Mpc. The colour bar of each plot is on the top of each panel. In general, blue colours represent less than the mean surface density of the field and red colours correspond to the highest density of each sample. Yellow and green denote intermediate densities. Dotted contours correspond to underdense regions (Σ/〈Σ〉 < 1), solid contours correspond to overdense regions (Σ/〈Σ〉 > 1) and dashed contours correspond to mean density regions (Σ/〈Σ〉 = 1). The red dashed circle centred on the star symbol has a radius of 10 h⁻¹ comoving Mpc.