観測[kansoku] observation
観測ヘリコプター[kansokuherikoputaa] observation helicopter
計測[keisoku] measurement
再測量[saisokuryou] resurvey
三角測量[sankakusokuryou] triangulation

実測[jissoku] survey
実測図[jissokuzu] measured map
写真測量[shashinsokuryou] photographic surveying
推測[suisoku] guess
測候所[sokkoujo] weather measurement station