Chapter 2: Representations of Earth – Maps and Our Views

A comprehensive set of practice flashcards covering Chapter 2 topics: cartography, map types, Earth’s shape and coordinates, the geographic grid, time, land survey systems, GNSS, map projections, scales, data types, remote sensing, and GIS.

What is cartography?

The science and art of making maps, including the design, production, and study of maps to represent spatial information and geographic relationships; modern maps are created with computers, satellites, and GIS.

What are the two fundamental categories of maps and how do they differ?

Reference maps show general geographic information (where things are); thematic maps highlight specific geographic features and encourage recognition of spatial patterns.

What question does a reference map answer, and what question does a thematic map answer?

Reference maps answer: 'What is there?' Thematic maps answer: 'What is the pattern of this thing?'

What is the Earth's shape and why?

The Earth is an oblate spheroid; the equator bulges outward due to Earth's rotation.

What are the approximate equator diameter and pole-to-pole diameter of Earth?

Equator diameter ≈ 12,758 km (7,927 miles); pole-to-pole diameter ≈ 12,714 km (7,900 miles).

What are the approximate Earth circumference values at the equator and pole-to-pole?

Equator circumference ≈ 40,075 km (24,901 miles); pole-to-pole circumference ≈ 40,008 km (24,860 miles).

How is the meter defined in relation to the Earth's meridian?

The meter is 1/10,000,000 of the distance from the North Pole to the Equator along a meridian.

What are the highest and lowest elevations on Earth?

Highest: Mt. Everest ≈ 8,850 meters (29,035 ft); lowest: Mariana Trench ≈ 11,033 meters (36,200 ft) below sea level.

Who is considered the Father of Geography and what did he determine?

Eratosthenes; he determined the polar circumference of the Earth using shadows from Syene (Aswan) and Alexandria, within about 1% of the true value.

What are globes and great circles?

Globes are spherical representations of the Earth; great circles are the largest circles on a sphere; great-circle routes are the shortest paths between two points; hemispheres and circle of illumination relate to these concepts.

What is latitude and longitude?

A coordinate system using parallels (latitude) and meridians (longitude) to locate places on the Earth; forms a graticule grid.

What are latitude lines and how are they measured?

Parallels that run east–west; measured in degrees (°), minutes ('), seconds (”); 0° is the Equator; 0–90° N or S.

How was latitude traditionally determined?

By measuring the angle between the horizon and a celestial body with a sextant.

What supports air and sea navigation today?

Satellite-based Global Positioning System (GPS) and other GNSS technologies.

What is longitude’s reference line and its range?

The prime meridian at 0° (Greenwich); longitudes range from 0° to 180° East or West (E/W).

What are meridians and how do they behave?

Meridians run north–south from pole to pole; they converge at the poles and are used with parallels to locate places.

What is the formula to convert degrees, minutes, seconds to decimal degrees?

Decimal Degrees = Degrees + (Minutes/60) + (Seconds/3600).

What is the approximate distance represented by 1° of latitude or longitude near the equator?

About 111 kilometers (69 miles).

What are graticules?

Lines showing parallels of latitude and meridians of longitude on the Earth.

How are time zones connected to longitude and time?

Time zones are based on longitude; the Earth rotates 360° in 24 hours (15° per hour), leading to standard time zones and the use of UTC/GMT as reference.

What is UTC and how does it relate to GMT and Zulu time?

UTC (Coordinated Universal Time) is based on atomic clocks; GMT is the historical term; Zulu time (Z) is a designation used by some militaries.

How are standard time zones typically arranged?

In belts of 15°, with boundaries often following natural or political boundaries to simplify timekeeping.

Why does the Sun appear to rise in the east and set in the west?

Because the Earth rotates toward the east, causing celestial objects to appear to move westward across the sky.

What is UPSS (Township and Range) and what are its basic units?

U.S. Public Lands Survey System; Townships are 6 miles on a side, divided into 36 sections of 1 square mile (640 acres) each; sections can be further divided into halves and quarters (e.g., 160 acres for a quarter section; 40 acres for a 40-acre tract).

What does T110N R50W signify in UPSS?

Township 110 North; Range 50 West—Brookings’ township location relative to a baseline and a principal meridian.

What does GNSS stand for and what is its purpose?

Global Navigational Satellite Systems; an umbrella term for satellite navigation systems used to determine location (latitude, longitude, elevation) on Earth.

Name four GNSS constellations commonly used today.

GPS (USA), GLONASS (Russia), Galileo (EU), BeiDou (China).

What is GIS and what does it do?

Geographic Information Systems; a system for storing, overlaying, and analyzing spatial data to solve problems and create thematic maps.

What are DEMs in GIS?

Digital Elevation Models; computer-generated 3-D representations of terrain showing elevation and vertical exaggeration.

What are the main types of map projections?

Planar (azimuthal), Conic, and Cylindrical (Mercator) projections.

Why do all map projections distort something?

Because a spherical Earth cannot be flattened without distortion; you cannot preserve all properties (size, shape, distance, and direction) simultaneously.

What is a conformal map?

A map that preserves local shapes (angles) but may distort size.

What is an equal-area map?

A map that preserves relative areas (size) but may distort shape.

What is a gnomonic projection and its navigational utility?

An azimuthal projection that shows all great circles as straight lines, making it useful for navigation despite distorting distances and shapes.

What are compromise projections?

Projections that balance area and shape rather than optimizing one at the expense of the other (e.g., Robinson, Goode homolosine).

What are the five essential map items every map should have?

Map title, date, north arrow, legend (key), and scale.

What are the types of map scales?

Verbal scale (e.g., 'one inch equals one mile'), representative fraction (RF, e.g., 1:24,000), and graphic (bar) scale.

What is the difference between a large-scale and a small-scale map?

A large-scale map shows a small area in great detail; a small-scale map covers a large area with less detail.

What are isolines and give two examples?

Lines that connect points of equal value; examples include isotherms (temperature) and isobars (pressure).

What is the difference between discrete and continuous data in maps?

Discrete data consist of points, lines, or polygons (vector); continuous data form a surface or grid (raster) where data exist across the space.

What is a lattice versus a grid in spatial layout?

A lattice is a repeating pattern of points; a grid is a network of evenly spaced lines forming squares or rectangles.

What is the purpose of topographic contour lines?

To represent land surface elevation on maps; contour spacing indicates gradient (closer lines mean steeper slope).

What is a bathymetric chart?

A chart that shows depth contours (isobaths) for underwater terrain, analogous to elevation contours on land.

What are the differences between remote sensing types: passive vs active?

Passive systems collect natural energy (e.g., reflected sunlight) via aerial or satellite imagery; active systems transmit energy (e.g., radar, LiDAR) and measure returning signals.

What is the difference between natural color and false color infrared imagery?

Natural color displays scenes as the human eye would see them; false color infrared uses infrared bands to highlight vegetation and other features.

What is multispectral versus hyperspectral imagery?

Multispectral uses a few broad spectral bands; hyperspectral uses many narrow bands for detailed material identification.

What is the role of DEMs in modern mapmaking?

DEM data provide 3-D representations of terrain used for visualization, analysis, and modeling in GIS.