"A contour line of a function of two variables is a curve along which the function has a constant value."
Definition and use of contour lines in topography.
Topographic Maps: Topographic maps are maps that show the features of the land, such as contour lines, elevations, and topography.
Contour Lines: Contour lines are lines on a topographic map that represent points of equal elevation.
Elevation: Elevation is the height of a point above sea level.
Relief: Relief is the difference in elevation between two points.
Slope: Slope is the steepness of a hill or mountain.
Gradient: Gradient is the rate at which a slope changes.
Topographical profiles: A topographical profile is a vertical slice through a topographic map that shows the elevation changes along a specific line.
GPS Devices: A GPS device is a device that can track your location using satellite technology.
Drawing Contour Lines: Learn how to plot contour lines onto a topographic map.
Reading Contour Lines: Learn how to read contour lines and understand the different patterns they create.
Map Scale: Map scale is a ratio used to represent the distance between two points on a map.
Legend: A legend provides information about the symbols and colors used on a map.
Map Orientation: Map orientation refers to the direction in which a map is facing.
Compass Rose: A compass rose is a symbol on a map that shows the cardinal directions (north, south, east, west).
Map Projections: Map projections are ways of representing the surface of the Earth on a flat surface.
Geographic Coordinates: Geographic coordinates are a system of coordinates that are used to locate points on the Earth's surface.
Datum: Datum is a reference point or a starting point used in making measurements.
Geographic Information System (GIS): A GIS is a software system designed to capture, store, manipulate, analyze, and display geographically referenced data.
Remote Sensing: Remote sensing is the process of collecting data about the Earth's surface from a distance, such as from satellites or airplanes.
Digital Elevation Models (DEM): A digital elevation model is a digital representation of the Earth's topography.
Index Contours: These are bold and numbered contour lines that represent a change in elevation, usually every fifth contour line.
Intermediate contours: These are the contour lines that fall between the index contours and represent smaller changes in elevation.
Supplementary contours: These are the small dashed lines used in areas with steep terrain where contour lines are closer together, they represent the elevation that is halfway between the indexed contour lines.
Depression Contours: These are contour lines that have hachures pointing towards the lower elevation, which represents a depression.
Ridge Contours: Ridge contours are the contour lines that represent a ridge or a top of a hill.
Valley Contours: These represent the contour lines that show a valley or low area between hills or mountains.
Cliff Contours: These are contour lines with small tick marks that represent vertical drop or cliffs.
Slope Contours: These represent the contour lines that are closely spaced and point uphill, they represent steep slopes.
Bench Contours: These are the contour lines that are resembled as flat steps which are found at places where the elevation is changing gradually.
Summit Contours: Shows the highest point of a hill or a mountain.
Saddle Contours: Saddle contours are the lines that represent low parts of a ridge or a valley, that is carved out between two high points of a terrain.
"A contour line joins points of equal elevation (height) above a given level, such as mean sea level."
"A contour map is a map illustrated with contour lines, for example, a topographic map."
"A contour map shows valleys and hills and the steepness or gentleness of slopes."
"The contour interval of a contour map is the difference in elevation between successive contour lines."
"The gradient of the function is always perpendicular to the contour lines."
"When the lines are close together, the magnitude of the gradient is large: the variation is steep."
"A level set is a generalization of a contour line for functions of any number of variables."
"Contour lines describe the intersection of a real or hypothetical surface with one or more horizontal planes."
"The configuration of these contours allows map readers to infer the relative gradient of a parameter."
"Contour lines may be traced on a visible three-dimensional model of the surface."
"Contour lines can be interpolated from the estimated surface elevations, as when a computer program threads contours through a network of observation points."
"The method of interpolation affects the reliability of individual isolines."
"Contour lines can portray the slope, pits, and peaks of a surface."
"Contour lines are also known as isolines, isopleths, isoquants, or isarithms."
"Contour lines can be curved, straight, or a mixture of both lines on a map."
"Contour lines allow map readers to estimate the parameter at specific places."
"When contour lines are close together, the magnitude of the gradient is large, indicating a steep variation."
"A photogrammetrist viewing a stereo-model can plot elevation contours on a visible three-dimensional model."
"A computer program can thread contours through a network of observation points to generate contour lines."