Contour Lines
Definition
Contour Lines are imaginary lines drawn on a map to connect points of equal elevation. These lines help represent the three-dimensional shape of the terrain on a two-dimensional map. The spacing and shape of the lines provide visual clues about slope, relief, and landscape form. Closely spaced lines indicate steep slopes, while wide spacing suggests gentle terrain.
Application
Contour lines are used in topographic maps, site analysis, watershed modeling, and infrastructure design. Surveyors use them to calculate cut and fill for construction. Geologists study them to interpret landform development. Environmental scientists use them in erosion control and slope stability assessment. GIS software generates contour lines from elevation datasets, enabling users to adjust contour intervals and apply symbology to improve readability and interpretability.
FAQ
How do contour lines represent terrain in GIS?
They visualize the surface shape by connecting points of equal elevation, revealing hills, valleys, and slopes.
What is a contour interval?
It is the vertical distance between two contour lines, which determines how detailed the elevation depiction is.
How are contour lines created?
They are derived from DEMs or TINs using GIS tools that perform elevation slicing and line generation.
Why are contour lines essential in planning?
They support elevation-based decision-making in construction, zoning, flood risk assessment, and agriculture.
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