2 sentences

1. 工程师们正在实地进行地形测绘。

   gōng​chéng​shī men zhèng​zài shí​dì jìn​xíng dì​xíng cè​huì.

   Engineers are conducting field topographical mapping.

   Source: Dong Chinese Dictionary

2. 工程师把这个固定标记点作为测绘的海拔基准。

   gōng​chéng​shī bǎ zhè​ge gù​dìng biāo​jì​diǎn zuò​wéi cè​huì de hǎi​bá jī​zhǔn.

   The engineer used this fixed marker as the elevation datum for the survey.

   Source: Dong Chinese Dictionary