Chapter 2: Portraying Earth - Maps, Projections, and Geospatial Technologies

Vocabulary flashcards covering Chapter 2: Portraying Earth, including globes, map scale, projections, isolines, GPS/GNSS, remote sensing, and GIS.

Globe

A true and actual depiction of Earth that maintains its spherical shape and undistorted spatial relationships, though only half can be viewed at one time and it cannot show much detail.

Map

A flat, two-dimensional representation of Earth portraying spatial relationships, regions, and basic properties such as size, shape, distance, and direction.

Thematic Map

A map designed to graphically depict additional, purposeful features and/or data.

Map Scale

The relationship between distance or measurement on a map and the actual distance or measurement on the ground.

Graphic Map Scale

A map scale consisting of a line marked off in distances to represent actual distance on the Earth's surface.

Fractional Map Scale (Representative Fraction)

A map scale expressing the relationship between distance measured on a map and actual distance on Earth as a fraction or ratio.

Verbal Map Scale (Word Scale)

A map scale that states in words the relationship between distance on the map and actual distance on Earth's surface.

Large-Scale Map

A map with a relatively large representative fraction and small denominator, used to show a small portion of Earth's surface in detail.

Small-Scale Map

A map with a small representative fraction and large denominator, used to show a relatively large area with limited detail.

Map Projection

The system or method by which Earth's curved surface is transformed for display on a flat surface.

Cartographer

A mapmaker who strives to combine the geographic exactness of a globe with the convenience of a flat map by controlling or reducing distortions.

Equivalent Map Projection (Equal Area)

A map projection that maintains the size ratio of areas from the map to the ground while distorting shapes, notably on small-scale maps.

Conformal Map Projection

A map projection that maintains proper angular relationships and shapes of locations while distorting area size.

Compromise Map Projection

A map projection that is neither equivalent nor conformal, balancing reasonably accurate shapes with reasonably accurate areas.

Cylindrical Projection

A projection created by wrapping the globe in a cylinder tangent at the equator, where distortion increases with increasing distance from the circle of tangency.

Mercator Projection

A conformal cylindrical projection used for navigation where area is mostly distorted at the poles.

Loxodrome (Rhumb Line)

A line on a sphere that crosses all meridians at the same angle.

Gnomonic Projection

A projection on which great circles are displayed as straight lines.

Planar Projection

An equivalent projection that projects the globe onto a flat surface at a point of tangency, typically showing one hemisphere with no distortion immediately around the tangent point.

Conic Projection

A projection formed by projecting the globe onto a cone with its base as a standard parallel, well adapted for mapping midlatitudes of east-west orientation.

Pseudocylindrical Projection

A projection mixing conformal and equivalent properties that wraps around a standard parallel, curves toward the poles, and features a central parallel and meridian intersecting at right angles without distortion.

Interrupted Projection

A discontinuous map (such as Goode's projection) that minimizes the distortion of landmasses by interrupting oceanic regions.

Legend

A map essential providing an explanation of symbols, colors, and shadings that represent features or data.

Isoline

A generic term for a closed line joining points of equal value on a map that cannot touch or cross another isoline.

Elevation Contour Line

A type of isoline that joins points of equal elevation.

Isotherm

A type of isoline that joins points of equal temperature.

Isobar

A type of isoline that joins points of equal atmospheric pressure.

Isohyet

A type of isoline that joins points of equal precipitation.

Isogonic Line

A type of isoline that joins points of equal magnetic declination.

Isoline Interval

The distance or numerical difference between adjacent isolines.

Global Navigation Satellite System (GNSS)

A system of satellite technologies providing precise location data, which includes the Global Positioning System (GPS) and similar systems.

Global Positioning System (GPS)

A satellite-based navigation system that calculates and displays detailed location information on Earth by triangulating signals with four or more satellites in view.

Wide Area Augmentation System (WAAS)

A system developed for aviation that utilizes ground-based stations to transmit location corrections to satellites.

Continuously Operating GPS Reference Stations (CORS)

A system of permanent GPS receivers managed by the National Oceanic and Atmospheric Administration (NOAA) for monitoring ground surface changes.

Remote Sensing

Any measurement of Earth collected by a device that is not in direct contact with Earth's surface.

Photogrammetry

The science of obtaining reliable measurements and mapping from aerial photographs.

Orthophoto Map

A multicolored, distortion-free photographic map prepared from aerial photographs or digital images that retains a common scale while displaying landscape detail.

Visible Light and Infrared (IR) Sensing

Remote sensing that detects certain wavelengths of the electromagnetic spectrum to reveal surface cover variations, often producing false-color images.

Thermal Infrared Sensing

Remote sensing scanning the thermal IR part of the spectrum to produce images based on temperature differences, such as between land and water.

Multispectral Remote Sensing

A remote sensing method that detects and records many bands of the electromagnetic spectrum simultaneously.

Landsat (Earth Resources Technology Satellite)

Early NASA space missions launched in the 1970s and 1980s that utilized multiband photography obtained through multicamera arrays.

Earth Observing System (EOS) satellites (Terra)

Satellites launched in 1999 that use the Moderate Resolution Imaging Spectroradiometer (MODIS) with $36$ spectral bands to provide images covering the planet every one to two days.

Radar

Radio detection and ranging; a remote sensing system capable of operating day and night and penetrating atmospheric moisture by sensing radio wavelengths.

Sonar

Sound navigation and ranging; a technology that uses sound waves to permit underwater imaging.

Lidar

Light and radar; a system that uses reflected laser light to measure distances and generate three-dimensional information about surface features.

Geographic Information Systems (GIS)

Computer systems designed to analyze and display spatial data by utilizing superimposed layers of information linked to location coordinates.

Overlay Analysis

A GIS procedure involving two or more data layers that are superimposed or integrated to analyze spatial relationships.