Shapefile of Historical Bathymetric Soundings for Mississippi and Alabama Derived from National Ocean Service (NOS) Hydrographic Sheets

Hydrographic sheets (H-sheets) and nautical charts produced by the National Ocean Service (NOS) during the 1800s provide historic sounding (water depth) measurements...由国家海洋服务局（National Ocean Service，简称NOS）于19世纪编制的水文图（Hydrographic sheets，简称H-sheets）与航海图，收录了具备历史价值的测深（水深）测量数据……