edubun
English
English한국어EspañolPortuguêsFrançaisDeutschItalianoNederlandsРусскийBahasa Indonesia日本語
Home›World geography

Map reading

Topographic maps squeeze hills, valleys and rivers onto flat paper. This course reads them the way surveyors and hikers do: symbols and colours, scale, direction and bearings, contour lines, slope, and cross-sections. A 3D model of the same land sits next to every map, so each line can be checked against the ground it describes. Conventions come from the USGS and the National Geographic Information Institute of Korea.

Progress

About this course

Topographic maps squeeze hills, valleys and rivers onto flat paper, and this course reads them the way surveyors and hikers do. A 3D model of the same land sits next to every map, so each line can be checked against the ground it describes. Conventions come from the USGS and the National Geographic Information Institute of Korea (NGII).

The six units are what a topographic map shows, map scale, direction, north and bearings, contour lines, reading slope from contours, and drawing a cross-section. Scale comes in three forms that describe one map: a scale bar, a ratio and words, and a practice question asks how far apart two villages 6 cm apart on a 1:25,000 map really are. Most maps are drawn with north at the top, but the NGII explains three norths: true north points along the meridian to the geographic North Pole, grid north follows the vertical grid lines printed on the map, and magnetic north is the direction a compass needle settles in.

Contour lines are the heart of the course. The height difference between neighbouring lines is the contour interval, printed in the margin, and every fifth contour is drawn thicker and labelled with its height as the index contour. The slope unit notes that doubling a 10 percent slope to 20 percent roughly doubles the angle, but going from 50 to 100 percent adds only about 18 degrees. In the last unit a profile is made honest by two details: a hilltop inside the 180 metre ring but with no 200 metre ring must rise above 180 and stay below 200, and the ends of the profile fall between contours, so their heights are estimates.

Before you start

Map scale is a ratio such as 1:25,000, so Ratio and proportion is the most useful preparation, and the slope unit turns a climb into a percentage. Knowing latitude and longitude from Continents and oceans also helps. A ruler is handy for measuring distances on a map.

When you finish

You can read a topographic map's colours and symbols, turn centimetres on a 1:25,000 map into metres on the ground, and give a bearing such as 180° for due south. You can explain the three norths on a map, read heights from contour lines, find a slope as a percentage, and draw a cross-section with a chosen vertical exaggeration.

  1. 1What a topographic map showsOn a USGS topographic map, brown lines are heights, blue is water and green is woodland, and the colours mean the same thing on every sheet.
  2. 2Map scaleOn a 1:25,000 map, 4 centimetres of paper stand for exactly 1 kilometre of ground.
  3. 3Direction, north and bearingsA topographic map can carry three different norths, and a compass needle follows only one of them, magnetic north.
  4. 4Contour linesOn a Korean 1:25,000 map a contour is drawn every 10 metres of height, and every fifth one is drawn thick.
  5. 5Reading slope from contoursClimb 100 metres while walking 500 metres across the map and the slope is 20 percent, an angle of about 11.3 degrees.
  6. 6Drawing a cross-sectionDraw a profile from a 1:24,000 map with a vertical scale of 1:200 and the hills look 120 times taller than they would at true scale.

Related courses

  • Continents and oceans
    Seven continents, five oceans, the highest and deepest places, the longest rivers and the driest deserts, then the grid of latitude and longitude, time zones and the maps that flatten the globe. Every number comes from the CIA World Factbook, NOAA, USGS or National Geographic.
  • Countries and capitals
    Spin a real globe, find countries by clicking them, and practise capitals continent by continent. Borders follow Natural Earth, a public map dataset used by atlases and news graphics.
  • Rivers and mountains
    Where does rain go after it lands, and why do mountains stand where they do? This course follows water from a single drop to a river mouth, reads drainage basins and divides on a 3D model, then turns to how mountains are built, the highest peaks, and the rivers and mountains of Korea. Numbers come from the USGS, the US Army Corps of Engineers, National Geographic Education and the National Geographic Information Institute of Korea.
  • Ancient civilizations · World history
    The first cities grew up beside rivers: the Tigris and Euphrates, the Nile, the Indus and the Yellow River. Eight units cover how those societies farmed, built, wrote, made laws and worked metal, with maps, timelines and flashcards. Dates before about 1000 BCE are approximate, and each unit says where scholars disagree.
Sources for this course (14)
  • USGS, Topographic Map Symbols (pubs.usgs.gov/gip/TopographicMapSymbols/topomapsymbols.pdf: colours, contours never cross, index contours wider, close contours = steep, interval 10 ft or less in flat areas, 100 ft or more in mountains, interval printed in the margin)
  • USGS FAQ Why are USGS topographic maps called quadrangles? (usgs.gov/faqs: 7.5-minute maps at 1:24,000, one inch = 24,000 inches = 2,000 feet; Alaska 1:25,000)
  • USGS Topographic Mapping (usgs.gov/educational-resources/topographic-mapping: 1:63,360 = 1 inch to 1 mile, accuracy 1/50 inch = 40 ft, half the contour interval)
  • USGS Map Scales fact sheet (pubs.usgs.gov/fs/2002/0015, 1:100,000 about 1.6 miles, 1:250,000 about 4 miles per inch)
  • USGS US Topo specifications, Elevation (index contour = every fifth contour)
  • 국토지리정보원(NGII): 지도의 구성 (ngii.go.kr/kor/content.do?sq=272: 진북·도북·자북, 도편각·도자각·자편각, 수치지형도 분류 교통·건물·시설·식생·수계·지형·경계·주기 8가지, 주곡선·계곡선·간곡선·조곡선, 경위도 원점과 수준원점 26.6871 m)
  • 「1/25000 및 1/50000 지형도도식규정」 국토지리정보원고시 제2009-584호 제129조 (law.go.kr: 주곡선 1/25,000 10 m, 1/50,000 20 m)
  • 「소축척지형도 도식적용규정」 (law.go.kr: 계곡선은 주곡선 다섯 개마다)
  • NOAA NCEI, Magnetic Declination (ncei.noaa.gov/products/magnetic-declination: angle between magnetic north and true north, east positive, changes with time and place; true bearing = magnetic bearing + declination)
  • NOAA NCEI Tracking Changes in Earth's Magnetic Poles (2018, updated: Ross 1831; pole moving about 55 km/yr in 2007, about 45 km/yr in the IGRF of that time)
  • NCEI news, 2025 WMM Annual Report is Released (9 Jan 2026: north magnetic pole average drift about 36 km/yr over the past year)
  • IOF ISOM 2017-2, symbol 601 Magnetic north line (magnetic north lines printed on the map, 20 mm = 300 m at 1:15,000, map rotated so the lines run parallel to the paper edges)
  • UK House of Commons Standing Orders (Private Business) 55: deposited railway section
  • The National Archives catalogue, King's Lynn to Spalding railway plan deposited 30 Nov 1850 (horizontal 6 chains = 132 yards to 1 inch, vertical 60 feet to 1 inch, VE 396/60 = 6.6).

Checked: 2026-10-18