benchmarkA survey marker in the ground with a measured height. It is often a bronze or aluminum disk set in stone or concrete.
contour intervalThe vertical gap between one line and the next. It varies from map to map, and each map states it in the margin.
contour lineA line along which the ground stays at one height. Walk along one and you go neither up nor down. The lines are imaginary: nothing marks them on the ground.
depression contourA closed line with tick marks, ringing a hollow. The short ticks, called hachures, point toward the low ground. Without them a closed loop is read as a hill.
elevationA ground height in meters or feet above the sea. Elevation is used for points on the ground. Altitude is used for things above it, such as an aircraft in flight.
index contourA heavier contour line marked with its height. Contour lines are printed in two thicknesses. Only the heavier ones carry numbers, in feet or in meters.
reliefThe range between high and low ground in an area. It is found by subtracting the lowest elevation in an area from the highest.
Show all 36 terms (29 more)
Reading contour lines, continued
sea levelThe ocean surface, averaged over tides and years. It is found by averaging the readings of a tide gauge over a long time. Heights such as elevation are measured from it.
slopeThe slant of the land, from level to very steep. Contour lines close together show a steep slope. Lines far apart show a gentle one.
spot elevationA number on the map giving the height of one point. Unlike a benchmark, it has no disk or plate on the ground. On the map it is often marked with a small cross.
topographic mapA detailed map from which land heights can be read. Contour lines give the land its shape on the page, and roads, rivers, lakes and place names are added. The United States Geological Survey made its first one in 1879.
topographic profileA side view of the land along a line across a map. It is usually drawn with the heights exaggerated three to five times, so that the relief shows clearly.
Landforms on the map 12
cliffA sheer drop, too steep to walk down. Cliffs are common on coasts, in mountains and along rivers.
depressionA hollow that is ringed by rising ground. A sinkhole is a depression made by collapse. A watering hole is one where water collects.
drainage divideThe high line that separates two river basins. Rain that falls on one side runs to one river, and rain on the other side to another. In hilly country the divide follows the ridges.
drawA strip of low, sloping ground between two spurs. In orienteering it is called a re-entrant.
floodplainThe flat valley floor that a river covers in flood. The river leaves sediment behind each time it floods. On a map the contour lines of a floodplain are far apart.
hillA rise in the land that a mountain would dwarf. It often has a distinct summit. On a map a hill is a set of closed contour lines, one inside another.
plateauHigh ground with a wide, nearly level top. At least one of its sides rises sharply from the lower country beside it, often as a steep escarpment.
ridgeA crest of high ground with a drop on each side. A ridge may stand less than a meter or hundreds of meters above the land beside it. In rugged country drainage divides follow the ridges.
saddleA dip between two higher points on a ridge. Where a saddle can be crossed, even if only on foot, it serves as a pass.
spurA short ridge that runs down from a hill or crest. A spur can also be a smaller range that juts sideways from a main mountain range.
summitThe crown of a hill, where every way leads down. On a map it lies inside the innermost closed contour line.
valleyLow ground between slopes, where water collects. A stream often runs along the bottom. Where contour lines cross a stream they bend into a V that points upstream.
Scale, direction and mapmaking 12
datumA fixed reference for measuring height or position. A datum works like the starting point in a set of directions. A horizontal datum is for latitude and longitude; a vertical datum is for land elevations and water depths.
hachuresShort lines drawn down a slope to show its steepness. They are an older way of showing relief, standardized in 1799. Having no numbers, they are less useful for measuring than contour lines.
legendThe list of a map's signs with the meaning of each. The United States Geological Survey uses one set of standard symbols on all its topographic maps.
lidarMeasuring distance by timing pulses of laser light. The name stands for light detection and ranging. Airplanes and helicopters most often carry the instrument.
magnetic declinationHow far a compass needle points away from true north. It varies from place to place and changes with time, so it has to be looked up for the place and the year.
magnetic northWhere the north tip of a compass needle points. The north magnetic pole is not at the geographic pole, and it moves over time.
map scaleHow much smaller the map is than the land it shows. A map gives its scale as a ratio, such as 1:50,000, and often as a bar to measure against.
quadrangleA map sheet bounded by latitude and longitude lines. The United States Geological Survey names each quadrangle after a local feature.
shaded reliefShading that makes hills look lit from one side. By convention the light shines from the upper left corner, so on a map with north at the top it seems to come from the northwest.
surveyingMeasuring distances and angles to fix points on land. The United States Geological Survey mapped in the field with a plane table until the 1940s, when aerial photographs took over.
true northThe direction toward the geographic North Pole. On a globe the lines of longitude lead to the true poles.
vertical exaggerationStretching the height scale to make relief stand out. It is used on raised-relief maps and cross sections, where heights drawn true to scale would be too small to make out.
How this list was compiled: Term list chosen for this site on 2026-10-12. Each meaning is written in our own words and was checked that day against the article on the term in the English Wikipedia (https://en.wikipedia.org/), whose text is under the Creative Commons Attribution-ShareAlike license: Topographic map, Contour line, Elevation, Terrain, Grade (slope), Benchmark (surveying), Sea level, Spot height, Topographic profile, Summit, Ridge, Valley, Saddle (landform), Mountain pass, Cliff, Spur (topography), Draw (terrain), Depression (geology), Hill, Plateau, Drainage divide, Floodplain, Scale (map), Map symbol, True north, North magnetic pole, Magnetic declination, Quadrangle (geography), Geodetic datum, Vertical exaggeration, Terrain cartography, Hachure map, Surveying and Lidar. Topographic maps, contour lines, index contours, the contour interval, steep slopes and the colors of the map were checked a second time against the U.S. Geological Survey (https://pubs.usgs.gov/fs/2001/0035/, Finding Your Way With Map and Compass; https://www.usgs.gov/faqs/what-a-topographic-map, What is a topographic map?; https://pubs.usgs.gov/gip/topomapping/topo.html, Topographic Mapping); slope, contour lines and the key of a map also against BBC Bitesize (https://www.bbc.co.uk/bitesize/articles/zjdkhbk, Contours, keys and symbols); datums and lidar against the National Ocean Service of the National Oceanic and Atmospheric Administration (https://oceanservice.noaa.gov/facts/datum.html, What is a datum?, and https://oceanservice.noaa.gov/facts/lidar.html, What is lidar?). The fact after each meaning is from the same pages. Licence: own work
How it works
This topographic map vocabulary worksheet lists contour line, contour interval, index contour, elevation, relief, slope, benchmark, sea level and four more terms beside their meanings in another order, with an answer key on the last page.
Read the full guide
Landforms on the map
Set opens on Reading contour lines. The second set has summit, ridge, valley, saddle, cliff, spur, draw, depression, hill, plateau, drainage divide and floodplain.
Scale, direction and mapmaking
The third set has map scale, legend, true north, magnetic north, magnetic declination, quadrangle, datum, vertical exaggeration, shaded relief, hachures, surveying and lidar.
Latitude, longitude and compass rose are words on the geography word search.
Questions and answers
What do the colors on a topographic map mean?
On United States Geological Survey maps contour lines are brown, water is blue and woodland is tinted green. Buildings are black, roads are red or black, and a purple overprint marks recent changes.
What does 1:24,000 mean on a map?
It is the scale: one unit on the map stands for 24,000 of the same unit on the ground, so one inch covers 2,000 feet. US Topo, the current map series of the U.S. Geological Survey, is drawn at this scale.
What is a 7.5-minute map?
A map sheet that covers 7.5 minutes of latitude by 7.5 minutes of longitude; a minute is a sixtieth of a degree. The United States Geological Survey produced its 7.5-minute series from about 1947 to 1992, each sheet covering 49 to 70 square miles.