Traverse mapping

[Lemma]

Никак не могу разобраться со следующими двумя предложениями. Буду очень благодарна за помощь!!

Traverse mapping was done on 500m by 300m grid line spacing. Each transverse line was mapped in details and results plotted onto a 1: 10 000 base map.

Это начало раздела Surface Mapping в отчете о проведенном геологическом исследовании.
На всякий случай, далее следует такой контекст :

The mapping results were then interpreted to produce a geological map of the area appendix 1.In areas where faulting was prevalent, the density of the grid lines was increased to a 100 x 100m grid. As area is generally confined to two major lithological units, the serpentinite and the pyroxenite, emphasis was placed on the structural mapping.