Complex sentence: The Department of Lands and Surveys also employed highly-skilled technical draftsmen, to prepare official maps representing the physical features of the territory and showing the boundaries and ownership of parcels of land, as these were brought back from field trips by the surveyors.
Split into simpler sentences: The Department of Lands and Surveys also employed highly-skilled technical draftsmen. They prepared official government maps representing the physical features of the territory and showing the boundaries and ownership of parcels of land, as these were brought back from field trips by the surveyors.