in this lecture i want to introduce tookgraphic maps specifically will be looking at some examples atopographic maps from here in ohio and then also a little bit more indetail that map to using an you're too graphic matlab assignmentwhich is assigned during weeks 1&2 1st october graphic maps ortypographical met symbols are used to locate and identify landmarks topography and other featuresand in the united states topographic maps are created by theunited states geological survey they include both natural features andcultural features
you can see two examples from the mentorarea here in northeast ohio where we can seethe cultural feature on the map circled in red that'slabeled community college that's why the map symbols for school you can also see then send the names andcontour lines and so on as well and then other on the right hand sideexample from the other harbor better memoranda harbor where you can seeroadways street names and so on which are alsocultural chairs on now the us have a graphic quadrangle
map series is one that we use a greatdeal and many applications and natural resources management and in geography ingis this is the example above the usgstopographic quadrangle out for mentor ohio it's part of the seven and ahalf minutes series which is produced in a mass scale 1224,000 this means that one inch on the map represents24,000 inches in reality or 1 inch represents 2000 beats the map includes a great deal ofinformation beyond just contour lines elevation
and physical features and also includesseveral grades and we'll talk for a moment about what those are how to read informationof those dreads personal latitude and longitude and we have an additional lecture filethat gives you the basics latitude longitude if you need a refresher %uh you tm cornets that's the universaltransfers mercator core that system which is a global courtsystem you learn about later on in the semester
and then the us public land surveysystem that will look out for just a moment a little bit later sir first at all the name seven-and-a-half minute seriesrelates to the geographic extent i'll these topographic maps so that the longitude extent allowed to text and isseven and a half minutes by seven and a half minutes you can see this up in the upper leftand right-hand corners on the map where you can see thelongitude up this particular map
it starts out over on the right handside it 81 degrees 15 minutes and 0 seconds west that isless to the global prime meridian and extends seven-and-a-half minutes tothe last to 81 degrees 22 minutes and thirty-seconds in terms of latitudethis particular map starts out and its southern extent at 41degrees 37 minutes and 30 seconds and extendsnorth to 41 degrees forty-five minutes north latitude that'sagain a difference out seven-and-a-half minutes you may locatelatitude and longitude lines along the edge on the map frame %uh thana usgs topographic
now in the case that the seven and ahalf minutes series you can start at the south mapping stepthat is the lower end afrin and new up the map until you seethe degree minutes or seconds abbreviation latitudeis designated every two and a half degrees or twominutes and thirty seconds and so every two-and-a-half how to locate large issue on usgs topographic map first i'll startat the eastern edge in the mapping stance the right side of the map frameand moved to the left until you see the
degree minutes or seconds abbreviation logic isdesignated every two-and-a-half minutes so that point acircled in green at the bottom of the screen is at 81 degrees 15 minutes and 0seconds west endpoint be as i 81 degrees seventyminutes and 30 seconds west a difference 7 house then it's then each map includes a great deal ofsupplemental information
so starting over in the lower left-handsection up the map first vote tells us is produced by theunited states geological survey using the north american datum 1983 andthe world geodetic system 1984 now what all this means is that the datum is basically a system that has been developed in order toupgraded model up the global that we can then produce maps on youlearn much more about de noms later on in the semester for now thoughknow that that's where you find out what the datum is when it was produced thebig
the most important to day times in thehistory of the usgs the 1927 datum that you'll see in someof the older maps and then also the 1983 which was thefirst system that was used up globally inorder to create a model of the day that using satellite technology and that'sstill kinda the standard data that's years and napping anadditional find more information about the details of how the actual mapwas created including the the magnetic declination and so you can see at the center the mapshe went in the magnetic declination
as and that's the difference between thegeographic north pole and the jeddah north pole %uh then in the center themap there's information about scale so inthis case it tells you that there's the scale 12 24,000 and again this would mean thatone inch on the map represents 24,000 inches in reality one centimeter represents twenty fourthousand seven meters in reality it also tells you contourinterval up ten feet which is the difference inelevation
between between councillors about 10 feet so every ten feetelevation difference there will be a new heart online thenorth american burgled a them 1988 was also use just a comment on thatif you see questions in your labs about which data is years were usuallytalking about the other day tum a 93 day and its use up for horizontal positioning opposition %uh then in the lowerleft-hand section up the map is a map key and it shows you a bitmore
about the map so well what do we see interms over patterns roads markings on the mapthings like that now the usgs house a much more details lap legend and a system where you can goand look at all the symbols they use they have dozens a different symbols that are usedon any up the maps and up and through their website theyhave more information about the other you can let us know if you havequestions on in addition there's a map locator
apartment locator in the lower write himso such a map so you can see there where itshows %uh mentor head to the western that the too graphic was called eastlake into thesouth that mayfield heights and so on linkages cents above the position under particular watching that you'relooking at time another series the usgs produces is the15 minute series topographic maps this is a smaller scale now than the seven-and-a-half minute series pointbeing that the geographic extent
is twice as large and so it's covering13 degrees latitude by 15 its longitude in this case the mapyou'll be working with which is storico map is at the scale of 62,500 that's not too far off other an areawhere you other map scale where 1 inch equals about one mile scale one to sixty 3,360 would be one it represents one mile iwant to bring up now that on does that we see someexamples you can use as cultural features hence
some other questions on the lab ask youabout %uh two different things that you maynot be familiar with one is up to estimate the extent ave section a bland and so basically this is something that you can answer withoutnecessarily doing any additional measurements on the map you can measurethat you want to there's no problem with that but you don't have need to measure it in order to answer itthe second hand is that cultural features displayed ontopographic what's sometimes reflect
local land-use practices and much in the western united statesmountain water sources were damned internet irrigation ditches in the late 19thcentury and there's evidence that this in the loveland colorado area especially on a 15 minute seriesmale so see if you can find labels names and features that might suggestsome other usages up other in the area and land uses iwant to conduct for a moment on the us congressional answered a
because this is part a the map in itsimportant parts and features a cultural features that you see on the matter the local and area because%uh the the road system follows therectangular grids laid out from the original public landsurvey it's also called the american landsurvey system the us for taking land survey and the township range system it goesback to the land ordinance active 1785 thomas jefferson set up the initialsystem
with the with the idea of providing ananswer to the question of how land would be settled to the west at the appellation mountainsat so the united states was a new country and one of the big questions was that there was a significant amount ofthe land a plan to the west of the appalachians in what would become ohio michiganindiana illinois wisconsin and minnesota and this becameknown as the northwest territory under the northwest ordinance active1787
so the first serving efforts wereactually carried out right here ohio an area not far from the i howevercall the seven rangers and then secondarilyand the a western reserve territory in this areanortheast ohio the basic system is based on creating abaseline that runs east and west and so ittypically would follow a particular parallel latitude and then oppress pomeranian which is aline running north and south follows ready and longitude and thelanding survey was
was divided into 36 square miletownships in other words townships that were six miles by six miles and then within thosetownships there was further subdivision intosections sections are one mile by one mile and most farms were settled in theunited states as one quarter sections and this is especially true after thehomestead act and 1862 when the initial survey systemwas put into place bombers were sold an entire section land640 acres
at one dollar acre and that proved to be first economically and bible for manypeople all significant mental and money at the time and too much land to maintain as well soin 1862 the congress passed the homestead act inpart to encourage settlement last doing so or and this allowed peoplethen stars in and porter sections this map shows areas in the united states that weresurvey using the us public land survey system butprincipal meridians and baselines
and will focus for now on the area thatwas surveyed in the loveland colorado case becausethis sideshows the area of the northwest territory togive you a sense out %uh how the original land surveysystem was laid out and how basically works and it's meantto kind of help harriett you towards the meeting outthese different survey lines and section numbers and things like that when yousee them on a topographic maps a first time are onohio here i'll had principal meridian and baselinerelated to the seven rangers which was
where survey experiments were taken out by thetime %uh the survey system at michigan and indiana were being done the systemhad been adjusted some pretty significant ways %uh so there are some changes anddifferences in how land were surveyed under the public land survey system western ohio than it is in this part ofohio but in the end i i the important thing that i want you tokeep in mind is that each other townships own example therein the center
the square township or north branch toeast that tells you that particular township is located is located 4 town lines north up the baseline and to range likes east and there's a rangeline every six miles in a township line every six miles and then each townshipcan be subdivided into sections and each section can then be subbed i did and order sections and corporatesupporters someone and so things like the phrase like thatnorth 40 for example he never heard that
relation to agriculture that comes from the subdivision as a a up the land into townships townships inthe section sections quarter sections and court is a quartersection but spoke is next on the area that was surveyed along with lovelandcolorado see and get a context up the geographic location have this place and how itrelates to the area where it was surveyed for so-called the baseline and principalmeridians that were used to serve a
colorado where the the baseline at 40 degreesnorth so the parallel but also forms the border between the states kansas andnebraska and the six principal meridian whichruns through the city of wichita kansas and so killers far to the east location out %uh loveland colorado so thatexplains why the range %uh range lines are 68 269 versus the township range only five to six because the baseline isonly about 30
or 40 miles to the south lovelandwhereas the prince already in is several hundred miles to the eastwhere you'll find the township and range numbers on the sidesof the up the map frame on the us geographicdemographic claude on is basically a red letters and thatcircle there %uh on the map on the bottom you findthe rangers the range between range 69 to the last at 69-68 to thewest there's a red line on the map thatdesignates that then there's a small red line that designates in the upper
right-hand corner of the map run thesite here township five north and townships its north on in many ways with theseven-and-a-half minute quadrangle maps up these are somewhat difficult to readthere aren't too many questions in your lab that ask you to do that but your assto locate one place based on its section number at latitude longitude coordinates don'twant to give you a sense of on how let the township and rangeboundaries her on these maps so in addition to thislecture be sure that you do the unit
reading assignment that has to do with reading topographic maps in trainingelevations on september graphic map i and then also watch the video whichdoesn't excellent job of summarizing how we bish allies three-dimensional space and we used tohave a graphic maps to do that contour lines to do that as well shows you how to read them how to makenow and how they're interpolated as well so that it that concludes this%uh lecture on topographic
maps