Types of Maps, Spatial Patterns, and Map Projections

Objective and Essential Learning

• Learning Objective 1.1: Identify types of maps, the types of information presented in maps, and different kinds of spatial patterns and relationships portrayed in maps.

• Essential Knowledge 1.1.1: Types of maps include reference maps and thematic maps.

• Essential Knowledge 1.1.2: Types of spatial patterns represented on maps include absolute and relative distance and direction, clustering, dispersal, and elevation.

• Essential Knowledge 1.1.3: All maps are selective in information; map projections inevitably distort spatial relationships in shape, area, distance, and direction.

Types of Reference Maps

• Definition of Reference Maps: Reference maps provide general information, location data, and spatial details required for navigation and geographic positioning.

• Political Maps: Display human-defined administrative boundaries, including states, national borders, and major capital cities.

• Physical Maps: Display natural environmental features, landforms, body of water boundaries, and terrain elevations.

• Elevation Categories on Physical World Maps:

  • Over $10,000\,\text{feet}$ / Over $3,050\,\text{meters}$

  • $5,001 - 10,000\,\text{feet}$ / $1,526 - 3,050\,\text{meters}$

  • $2,001 - 5,000\,\text{feet}$ / $611 - 1,525\,\text{meters}$

  • $1,001 - 2,000\,\text{feet}$ / $306 - 610\,\text{meters}$

  • $0 - 1,000\,\text{feet}$ / $0 - 305\,\text{meters}$

• Road Maps: Detail transportation routes and ground infrastructure, including major highways, local streets, arterial thoroughfares, and interstate transit corridors.

Types of Thematic Maps

• Definition of Thematic Maps: Maps designed to communicate spatial aspects, attributes, and specific quantitative or qualitative characteristics about a place, answering the question: "What is it like there?"

Choropleth Maps

• Definition: Utilize different colors, varying shades of a single color, or distinct fill patterns to illustrate the location, density, and distribution of spatial data across defined political or administrative units.

• Case Study (Mean Years of Schooling, 2017):

  • Data presented by Our World in Data (Sources: Lee-Lee (2016), Barro-Lee (2018), and UNDP HDR (2018)).

  • Measures the average number of total years of schooling across all education levels for the population aged $25+$.

  • Data Intervals: No data, $0\,\text{years}$, $2\,\text{years}$, $4\,\text{years}$, $6\,\text{years}$, $8\,\text{years}$, $10\,\text{years}$, $12\,\text{years}$, and $>14\,\text{years}$.

Dot-Density Maps

• Definition: Maps where individual dot symbols are placed across a map, with each dot representing a specific quantitative count of a spatial characteristic or occurrence.

• Case Study (Gun Violence in Cincinnati, Ohio):

  • Displays urban crime concentration in specific municipal districts including Over-the-Rhine, West End, Brewery District, Dayton Street Historic District, and Betts-Longworth Historic District.

Graduated / Proportional Symbol Maps

• Definition: Utilize map symbols (such as circles or bubbles) scaled to different sizes to represent proportional quantities or varying intensities of a variable; larger symbols represent higher magnitudes.

• Case Study (Largest Foreign-Born Group in Each U.S. County):

  • Created by Matthew Bloch and Robert Gebeloff for The New York Times (Sources: Social Explorer, Minnesota Population Center, U.S. Census Bureau).

  • Bubble diameter indicates overall population magnitude; bubble color indicates origin category:

    • Canada

    • Western Europe

    • Asia, Middle East

    • Latin America

    • Russia, E. Europe

    • Africa

Cartograms

• Definition: Maps in which land area or country boundary shapes are intentionally distorted and resized to scale directly with a chosen statistical variable.

• Case Study 1 (Population of Africa in 2018):

  • Data by Max Roser for Our World in Data (UN Population Division, Version 1, September 2018).

  • Each grid square unit represents $500,000\,\text{people}$.

  • Total Population of Africa: $1.288\,\text{billion}$ ($16.9\%$ of total world population).

  • Selected Country Data:

    • Nigeria: $195.9\,\text{million}$

    • Ethiopia: $107.5\,\text{million}$

    • Egypt: $99.4\,\text{million}$ (Greater Cairo: $20.5\,\text{million}$)

    • Democratic Republic of the Congo (D.R. Congo): $84\,\text{million}$

    • Tanzania: $59.1\,\text{million}$

    • South Africa: $57.4\,\text{million}$

    • Kenya: $51\,\text{million}$

    • Algeria: $42\,\text{million}$

    • Sudan: $41.5\,\text{million}$

    • Morocco: $36.2\,\text{million}$

    • Angola: $30.8\,\text{million}$

    • Mozambique: $30.5\,\text{million}$

    • Ghana: $29.5\,\text{million}$

    • Madagascar: $26.3\,\text{million}$

    • Cote d'Ivoire: $24.9\,\text{million}$

    • Cameroon: $24.7\,\text{million}$

    • Niger: $22.3\,\text{million}$

    • Burkina Faso: $19.8\,\text{million}$

    • Mali: $19.1\,\text{million}$

    • Malawi: $19.2\,\text{million}$

    • Zambia: $17.6\,\text{million}$

    • Zimbabwe: $16.9\,\text{million}$

    • Senegal: $16.3\,\text{million}$

    • Chad: $15.4\,\text{million}$

    • Somalia: $15.2\,\text{million}$

    • South Sudan: $12.9\,\text{million}$

    • Rwanda: $12.5\,\text{million}$

    • Tunisia: $11.7\,\text{million}$

    • Benin: $11.5\,\text{million}$

    • Burundi: $11.2\,\text{million}$

    • Togo: $8\,\text{million}$

    • Sierra Leone: $7.7\,\text{million}$

    • Libya: $6.5\,\text{million}$

    • Congo: $5.4\,\text{million}$

    • Eritrea: $5.2\,\text{million}$

    • Liberia: $4.9\,\text{million}$

    • Central African Republic (C.A.R.): $4.7\,\text{million}$

    • Mauritania: $4.5\,\text{million}$

    • Namibia: $2.6\,\text{million}$

    • Botswana: $2.3\,\text{million}$

    • Lesotho: $2.3\,\text{million}$

    • Gambia: $2.2\,\text{million}$

    • Gabon: $2.1\,\text{million}$

    • Guinea-Bissau: $1.9\,\text{million}$

    • Swaziland: $1.4\,\text{million}$

    • Equatorial Guinea: $1.3\,\text{million}$

    • Mauritius: $1.3\,\text{million}$

    • Djibouti: $1\,\text{million}$

    • Reunion: $0.9\,\text{million}$

    • Comoros: $0.8\,\text{million}$

    • Western Sahara: $0.6\,\text{million}$

    • Cape Verde: $0.6\,\text{million}$

    • Mayotte: $0.3\,\text{million}$

    • Sao Tome and Principe: $0.2\,\text{million}$

    • Seychelles: $0.1\,\text{million}$

• Case Study 2 (World Population in 2018):

  • Data by Max Roser for Our World in Data.

  • Contains $15,266\,\text{squares}$ representing $7.633\,\text{billion}\,\text{people}$.

  • Continental Totals and Major Country Breakdown:

    • Asia Total: $4.568\,\text{billion}$ ($59.8\%$ of world population).

      • China: $1.415\,\text{billion}$ ($18.5\%$ of world population)

      • India: $1.354\,\text{billion}$ ($17.7\%$ of world population)

      • Indonesia: $266.8\,\text{million}$

      • Pakistan: $200.8\,\text{million}$

      • Bangladesh: $166.4\,\text{million}$

      • Japan: $127.2\,\text{million}$

      • Philippines: $106.5\,\text{million}$

      • Vietnam: $96.5\,\text{million}$

      • Iran: $82\,\text{million}$

      • Turkey: $81.9\,\text{million}$

      • Thailand: $69.2\,\text{million}$

      • Myanmar: $53.9\,\text{million}$

      • South Korea: $51.2\,\text{million}$

    • Africa Total: $1.288\,\text{billion}$ ($16.9\%$ of world population).

    • Europe Total: $711\,\text{million}$ ($9.3\%$ of world population).

      • Russia: $144\,\text{million}$ ($34\,\text{million}$ in Asian part)

      • Germany: $82.3\,\text{million}$

      • United Kingdom: $66.0\,\text{million}$

      • France: $65.2\,\text{million}$

      • Italy: $60.3\,\text{million}$

      • Spain: $46.4\,\text{million}$

      • Ukraine: $44\,\text{million}$

      • Poland: $38.1\,\text{million}$

    • North America, Central America and Caribbean Total: $587\,\text{million}$ ($7.7\%$ of world population).

      • United States: $326.8\,\text{million}$ ($4.3\%$ of world population)

      • Mexico: $130.8\,\text{million}$

      • Canada: $37\,\text{million}$

    • South America Total: $428\,\text{million}$ ($5.6\%$ of world population).

      • Brazil: $210.9\,\text{million}$ ($2.8\%$ of world population)

      • Colombia: $49.5\,\text{million}$

      • Argentina: $44.7\,\text{million}$

      • Venezuela: $32.4\,\text{million}$

      • Peru: $30.6\,\text{million}$

      • Chile: $18.2\,\text{million}$

      • Ecuador: $16.9\,\text{million}$

    • Oceania Total: $41\,\text{million}$ ($0.5\%$ of world population).

      • Australia: $24.8\,\text{million}$

      • Papua New Guinea: $8.4\,\text{million}$

      • New Zealand: $4.7\,\text{million}$

Isoline Maps

• Definition: Maps that employ lines to connect points of equal numeric value to display continuous variable changes across space. Used extensively in weather forecasting and topography.

• Example Application: Continental United States temperature distributions on January 31st, 2019.

Topographic Maps

• Definition: Specialized maps that show structural surface elevation and terrain changes.

• Methods of Representing Elevation:

  • Contour Lines: Isolines connecting points of equal elevation. Slope steepness is portrayed through line spacing; lines positioned close together indicate steep terrain, whereas lines farther apart represent flat or gently sloping surfaces.

  • Textured / Shaded Relief: Uses shading gradients and surface texture across areas of the map to visually represent elevation changes and landscape depth.

• Example Map Source: U.S. Geological Survey (USGS) Topography map of Mount Desert Quadrangle, State of Maine (contour interval $20\,\text{feet}$).

Spatial Patterns on Maps

Absolute vs. Relative Location

• Absolute Location: The exact, precise point where a place or feature is situated on the surface of the Earth.

  • Expressed through precise street addresses (e.g., 6277 Autumnleaf Ln, Cincinnati, OH 45230 or 3200 Ebenezer Rd, Cincinnati, OH 45248).

  • Expressed through the geographic grid system of Latitude and Longitude coordinates.

  • Example Coordinate: Rio de Janeiro is located at $23^\circ\text{S}, 43^\circ\text{W}$.

• Procedure to Find Coordinates (e.g., Rio de Janeiro):

  • Step 1: Locate the parallel of latitude that is $23^\circ$ south of the Equator ($0^\circ$).

  • Step 2: Trace along that line to its intersection with the Prime Meridian ($0^\circ$ longitude).

  • Step 3: Move west along the same parallel until reaching $43^\circ$ west longitude.

• Relative Location: The position of a place described in relation to another known place or feature.

  • Examples: "Next to my house" or "Between Werk and Lawrence".

Absolute vs. Relative Distance

• Absolute Distance: Precise physical space measured between two points using standard linear spatial units (miles, kilometers, feet, meters).

  • Example: Oak Hills is exactly $21.3\,\text{miles}$ away from a home location.

  • Map Scale Formats:

    • Ratio / Fractional Scale: Expresses proportion between map distance and ground distance (e.g., $1 : 62,500$).

    • Graphic Scale: A visual bar showing measured ground distances ($0, 1, 2, 3, 4\,\text{miles}$).

    • Verbal Scale: Direct written statement (e.g., "$1\,\text{inch} = 1\,\text{mile}$").

• Relative Distance: Measure of distance based on travel time, financial cost, or degree of spatial interaction.

  • Spatial Interaction: The connections, contact, movement, and flow of goods, people, or information between locations.

  • Impact of E-Commerce: Companies like Amazon have drastically reduced relative distance between consumers and products (ordering items via Amazon Prime for home delivery within two days).

• Travel Route Comparisons (Cincinnati, OH Locations):

  • Route 1: $34\,\text{min}$ ($21.3\,\text{mi}$) via I-471 N

  • Route 2: $37\,\text{min}$ ($20.0\,\text{mi}$) via Columbia Pkwy

  • Route 3: $43\,\text{min}$ ($20.9\,\text{mi}$) via Ohio River Scenic Byway

Direction, Clustering, and Spatial Associations

• Absolute Direction: Exact directional measurement based on a fixed compass grid.

  • Cardinal Directions: North, South, East, West (NSEW) and intermediate points (NW, NE, SW, SE).

• Relative Direction: Directional descriptions based on situational context, personal orientation, or surrounding spatial landmarks.

  • Example: "Turn left at the Target, then right at the second stop-sign."

• Clustering: Objects or phenomena positioned close together in space.

  • Density: The total numeric count of something within a specifically defined area.

• Dispersal / Distribution: Objects or phenomena positioned far apart or spread out across space.

  • Distribution: The overall spatial arrangement and placement of something across an area.

• Patterns & Spatial Associations: Evidence or indication that two or more distinct spatial phenomena are related, interconnected, or correlated with one another.

Map Projections and Distortions

• Definition of Map Projection: The mathematical process by which a cartographer (map maker) projects the curved, three-dimensional surface of the Earth onto a flat, two-dimensional surface.

• The Earth's True Shape: The Earth is an irregular three-dimensional geoid with gravitational and topographic variations across its surface.

Map Distortion Mnemonic: S.A.D.D.

• Because a 3D sphere cannot be transformed onto a 2D plane without modification, all map projections inevitably distort spatial relationships.

• S - Shape: Distortion of the outline or geometry of landmasses.

• A - Area: Distortion of the relative size and proportions of landmasses.

• D - Distance: Distortion of the measured distance between locations.

• D - Direction: Distortion of compass orientation and angles between points.

Key Map Projections

Mercator Projection (1569)

• Primary Purpose: Maritime Navigation.

• Advantages: Preserves directional accuracy and local shape; maintains right-angle ($90^\circ$) intersections of latitude and longitude lines.

• Disadvantages: Severely distorts land area near the high latitudes, making landmasses closer to the poles appear disproportionately large.

• Classic Distortion Example (Africa vs. Greenland):

  • On a Mercator projection map, Greenland appears roughly equal in surface area to the continent of Africa.

  • In physical reality, Africa ($30.37\,\text{million}\,\text{km}^2$) is approximately 14 times larger than Greenland ($2.16\,\text{million}\,\text{km}^2$).

Peters Equal Area Projection

• Primary Purpose: Accurate land surface area comparison.

• Advantages: Preserves relative land area accurately, restoring equatorial and developing countries to their true comparative proportions.

• Disadvantages: Distorts land shapes near the poles and stretches landmasses vertically near the equator.

Robinson Projection

• Primary Purpose: General world display / compromise visualization.

• Advantages: Balances shape, area, distance, and directional distortion across the entire grid without extreme distortion in any single category.

• Disadvantages: Because it is a compromise projection, every spatial attribute (S.A.D.D.) contains slight distortion.

Other Special Projection Types

• Conic Projection: Surface projected onto a cone; preserves shape along standard parallels; frequently used for mid-latitude regional mapping.

• Azimuthal Projection (Polar / Planar): Surface projected onto a flat plane tangent to a single point (often a pole); provides true directions and distances from the central point.

• Fuller Projection (Dymaxion): Surface projected onto a multi-faceted polyhedron; preserves landmass shape and area with interrupted ocean surfaces.

Conclusion on Map Selectivity

• Every map is selective in the information it displays, and all two-dimensional projections distort the Earth's physical spatial relationships in some manner.