b'measuring and marking land for public use established, surveyors began to setis known as the federal survey system. It boundaries and describe the land in rela-was first used in eastern Ohio in an area tion to them. Permanent markers (usuallyjust west of the Ohio River. This survey metal stakes and pins in the ground)was called the Seven Ranges.would be laid, and boundaries could beOther Ohio surveys soon followed. proven. This system of surveying land wasOne of them set the Ohio-Indiana state carried into many other American lands,line, called the First Principal Meridian. too, as the country grew. Grids were notThe main latitude line to intersect, or always established in 6-mile x 6-mile sec-cross, that longitude line was set at the tions, but the rectangular system was imi-41N Latitude. Once these two lines were tated because it worked so well.Along the Ohio TrailA surveyor is someone who takes measurementsof the land and sets markers to show boundary lines.He or she cannot use things like rivers, trees,rocks, or other land forms to do this becausethey change over time. Instead, a surveyoruses the surface of the Earth.The Earths surface is described by usingtwo sets of lines: longitude lines (which runnorth and south) and latitude lines (which run westand east). These lines make a kind of grid over the Earths surface, likean invisible "net" that hugs the planet.The central longitude line (marked as 0 Longitude) is called thePrime Meridian and runs through Greenwich, England. Longitude linesthat run nearly parallel to the west of the meridian are measured as Wand those that run nearly parallel to the east of the meridian aremeasured as E. The central latitude line (marked as 0 Latitude) is called theEquator and runs around the world through South America and Africaprimarily. Latitude lines that run parallel to the north of the equatorare measured as N and those that run parallel to the south of theEquator are measured as S. A single, tiny spot on the earth can be measured using these lines.That spot can be named and recorded as the place where a latitude lineand a longitude line cross. For instance, Columbus, Ohio, is 40NLatitude, 8330W Longitude. Always name the latitude line first,longitude line second.page 35'