Topography and Related Topics

Terrain

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A shaded and colored image (i.e. terrain is enhanced) of varied terrain from the Shuttle Radar Topography Mission. This shows elevation model of New Zealand's Alpine Fault running about 500 km (300 mi) long. The escarpment is flanked by a vast chain of hills between the fault and the mountains of New Zealand's Southern Alps. Northeast is towards the top.

Terrain or relief (also topographical relief) involves the vertical and horizontal dimensions of land surface.

Geographic information system

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Type of database containing geographic data (that is, descriptions of phenomena for which location is relevant), combined with software tools for managing, analyzing, and visualizing those data.

E. W. Gilbert's version (1958) of John Snow's 1855 map of the Soho cholera outbreak showing the clusters of cholera cases in the London epidemic of 1854

Example of hardware for mapping (GPS and laser rangefinder) and data collection (rugged computer). The current trend for geographical information system (GIS) is that accurate mapping and data analysis are completed while in the field. Depicted hardware (field-map technology) is used mainly for forest inventories, monitoring and mapping.

Hillshade model derived from a digital elevation model of the Valestra area in the northern Apennines (Italy)

An example of use of layers in a GIS application. In this example, the forest-cover layer (light green) forms the bottom layer, with the topographic layer (contour lines) over it. Next up is a standing water layer (pond, lake) and then a flowing water layer (stream, river), followed by the boundary layer and finally the road layer on top. The order is very important in order to properly display the final result. Note that the ponds are layered under the streams, so that a stream line can be seen overlying one of the ponds.

A traditional topographic map rendered in 3D

OGC standards help GIS tools communicate.

While the basic elements of topography and theme existed previously in cartography, Snow's map was unique due to his use of cartographic methods, not only to depict, but also to analyze clusters of geographically dependent phenomena.

Bathymetry

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Study of underwater depth of ocean floors , lake floors, or river floors.

First printed map of oceanic bathymetry, produced with data from USS Dolphin (1853)

The seafloor topography near the Puerto Rico Trench

Present-day Earth bathymetry (and altimetry). Data from the National Centers for Environmental Information's TerrainBase Digital Terrain Model.

In other words, bathymetry is the underwater equivalent to hypsometry or topography.

Surveying

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Technique, profession, art, and science of determining the terrestrial two-dimensional or three-dimensional positions of points and the distances and angles between them.

A plumb rule from the book Cassells' Carpentry and Joinery

A map of India showing the Great Trigonometrical Survey, produced in 1870

A railroad surveying party at Russel's Tank, Arizona in the 1860s

A German engineer surveying during the First World War, 1918

A standard Brunton Geo compass, still used commonly today by geographers, geologists and surveyors for field-based measurements

Example of modern equipment for surveying (Field-Map technology): GPS, laser rangefinder and field computer allows surveying as well as cartography (creation of map in real-time) and field data collection.

Center for Operational Oceanographic Products and Services staff member conducts tide station leveling in support of the US Army Corps of Engineers in Richmond, Maine.

A survey using traverse and offset measurements to record the location of the shoreline shown in blue. Black dashed lines are traverse measurements between reference points (black circles). The red lines are offsets measured at right angles to the traverse lines.

The pundit cartographer Nain Singh Rawat (19th century) received a Royal Geographical Society gold medal in 1876, for his efforts in exploring the Himalayas for the British

An all-female surveying crew in Idaho, 1918

Surveying students with their professor at the Helsinki University of Technology in the late 19th century

Since the early days of surveying, this was the primary method of determining accurate positions of objects for topographic maps of large areas.

Landform

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Natural or artificial land feature on the solid surface of the Earth or other planetary body.

Karst towers landforms along Lijiang River, Guilin, China

Landforms together make up a given terrain, and their arrangement in the landscape is known as topography.

Theodolite

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Precision optical instrument for measuring angles between designated visible points in the horizontal and vertical planes.

Diagram of an optical readout theodolite

A typical modern electronic theodolite: Nikon DTM-520

thumb|upright|Jesse Ramsden's Great Theodolite of 1787

A theodolite of 1851, showing the open construction, and the altitude and azimuth scales which are read directly

A theodolite of the transit type with six-inch circles, manufactured in Britain c. 1910 by Troughton & Simms

Wild T2 theodolite originally designed by Heinrich Wild in 1919

Sectioned Wild theodolite showing the complex light paths for optical readout, and the enclosed construction

thumb|U.S. National Geodetic Survey technicians observing with a 0.2 arcsecond (≈ 0.001 mrad or 1 µrad) resolution Wild T3 theodolite mounted on an observing stand. Photo was taken during an Arctic field party (c. 1950).

Martin Waldseemüller, a topographer and cartographer made the device in that year calling it the polimetrum.

Triangulated irregular network

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Representation of a continuous surface consisting entirely of triangular facets (a triangle mesh), used mainly as Discrete Global Grid in primary elevation modeling.

Associated with three-dimensional data and topography, TINs are useful for the description and analysis of general horizontal distributions and relationships.

Contour line

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Curve along which the function has a constant value, so that the curve joins points of equal value.

A three-dimensional surface, whose contour graph is below.

A two-dimensional contour graph of the three-dimensional surface in the above picture.

Edmond Halley's New and Correct Chart Shewing the Variations of the Compass (1701)

Video loop of isallobars showing the motion of a cold front

The 10 C mean isotherm in July, marked by the red line, is commonly used to define the border of the Arctic region

Topographic map of Stowe, Vermont. The brown contour lines represent the elevation. The contour interval is 20 feet.

Isogonic lines for the year 2000. The agonic lines are thicker and labeled with "0".

From economics, an indifference map with three indifference curves shown. All points on a particular indifference curve have the same value of the utility function, whose values implicitly come out of the page in the unshown third dimension.

A single production isoquant (convex) and a single isocost curve (linear). Labor usage is plotted horizontally and physical capital usage is plotted vertically.

Contour map labeled aesthetically in an "elevation up" manner.

For example, in the topographic map above, the even hundred foot elevations are shown in a different weight from the twenty foot intervals.

A surface with a sample of normal vectors

Geomorphometry

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Science and practice of measuring the characteristics of terrain, the shape of the surface of the Earth, and the effects of this surface form on human and natural geography.

Slope effect of vegetation that is different on north-facing and south-facing slopes.

Map depicting cut and fill areas for a construction site.

Geomorphometrics is the discipline based on the computational measures of the geometry, topography and shape of the Earth's horizons, and their temporal change.