Topographic

Topographic describes the arrangement and representation of the natural and artificial features of the Earth's surface. It relates to topography, the description of terrain shape, position, and elevations, as well as to the study of how landscapes are formed and altered by natural processes and human activity.

Topographic maps show surface features with symbols, shading, and especially contour lines that connect points of equal elevation. The spacing of contour lines indicates slope: closely spaced lines for steep terrain, wider spacing for gentle slopes. Maps may use color shading, relief shading, and digital representations to convey three-dimensional form.

Data used to construct topographic information come from field surveys, aerial and satellite imagery, photogrammetry, and remote sensing technologies such as lidar and radar. Digital elevation models and geospatial datasets incorporate vertical and horizontal datums to align elevations with a reference surface.

Topographic knowledge supports planning, engineering, and environmental management, including watershed analysis, land-use planning, infrastructure design, disaster response, and outdoor recreation. It is essential for navigation, climate and hydrology studies, and any work involving terrain characterization.

Key related concepts include bathymetry, which maps underwater topography, relief, and terrain analysis. The accuracy and resolution of topographic data depend on measurement methods, data sources, and the chosen coordinate and vertical reference systems.