Overview
This lecture covers the main types of maps, map projections, geospatial data, methods of geographic inquiry, and essential spatial concepts for understanding both human and physical geography. It also explains how geographers use different tools and data to answer geographic questions and analyze spatial patterns.
Types of Maps
- Reference maps: Provide general geographic information for the public, such as roads, political boundaries, and topographic features. These maps are used for basic navigation and understanding of locations.
- Thematic maps: Focus on the spatial distribution of a specific phenomenon or data set (e.g., election results, population density). Thematic maps highlight one pattern at a time and do not show landscape features.
- Types of thematic maps:
- Choropleth map: Uses various colors or degrees of shading to show patterns of occurrence.
- Graduated symbol map: Uses symbols of different sizes to represent the frequency of an observation; larger symbols indicate higher frequency.
- Isoline map: Connects points of equal value with lines; all points along a line share the same value.
- Cartogram map: Adjusts the size of areas proportionally to the intensity of a particular observation, distorting the shape of the study area.
- Dot density map: Uses dots to represent the frequency of occurrences.
- Heat map: Uses color intensity to represent the frequency or intensity of observations.
Map Types & Features
- Heat map: Represents data values with colors by intensity, showing how frequent or intense observations are in different areas.
- Graduated symbol map: Displays the frequency of observations using symbols; the larger the symbol, the higher the frequency observed.
- Isoline map: Shows lines that connect points of equal value, so every observation along the same line has the same value.
- Dot density map: Uses dots to indicate the frequency of an occurrence, helping visualize distribution.
- Choropleth map: Shows patterns of occurrences using different colors or degrees of shading to represent data values.
- Cartogram map: Alters the size of areas based on the intensity of a particular observation, which warps the shape of the study area to reflect data.
Map Projections
- Mercator/cylindrical projection: Represents the globe as a rectangle, accurate at the equator but distorts distances and the size of land masses, especially near the poles. Most accurate at the equator, highly exaggerated around the poles.
- Conic projection: Projects the globe onto a cone with the point over the North Pole; most accurate in the mid-latitudes, commonly used for regional maps.
- Polar/azimuthal projection: Projects the globe from the perspective of the pole, showing true compass directions. Most accurate at the pole, but distorts size around the edges.
- Robinson/compromise projection: Maintains overall shape without extreme distortion by slightly distorting every characteristic. Balances size and shape for a more visually pleasing map.
- Equal area projection: Preserves the relative size of regions, so areas keep their true size, but shapes and angles are distorted. Useful for comparing the size of different regions.
Map Scale and Grid System
- Map scale: Shows the relationship between the distance on a map and the actual distance on Earth's surface. Represented in three ways:
- Representative fraction (RF): A ratio or fraction (e.g., 1:100,000).
- Verbal scale: Expressed in words (e.g., "one inch equals one mile").
- Visual scale: Displayed as a bar or graphic scale.
- Small scale maps: Show large areas with limited detail, such as world or country maps.
- Large scale maps: Show small areas with greater detail, such as city or neighborhood maps, and are used in GPS.
- Grid system: Used to pinpoint locations on Earth's surface, most commonly with latitude (measuring north-south) and longitude (measuring east-west).
Data in Geography
- Quantitative data: Specific, objective data that tells what and where something is. Examples include measurements, counts, and statistics.
- Qualitative data: Subjective, less specific data that explains why something occurs. Includes descriptions, interviews, and observations.
- Geospatial data: Any quantitative or qualitative data tied to a geographic location. This data is essential for mapping and spatial analysis.
Geospatial Technologies
- Geo-referencing: Linking a data record to a specific geographic location, allowing data to be mapped.
- GIS (Geographic Information System): Combines multiple layers of information into single maps, enabling complex geographic analysis and helping answer geographic questions.
- GPS (Global Positioning System): Uses satellites to provide precise location information; requires contact with four satellites for accuracy.
- Remote sensing: Collects data from a distance, such as via satellites, high-flying drones, or sound waves, to gather information about Earth's surface.
- Satellite imagery: Images taken from satellites, used for analysis, mapping, and monitoring changes over time.
- Demographic data: Statistical data about people, often collected through a census, used to analyze population patterns and trends.
Geographic Inquiry
- Observation: The starting point of geographic inquiry, involving collecting information through watching, measuring, using senses, and consulting primary or secondary sources.
- Visual aids: Tools that help geographers interpret and make sense of data, including photos, maps, charts, graphs, and satellite images.
- Maps: Essential for displaying and analyzing spatial data, helping to visualize patterns and relationships.
- Quantitative and qualitative data: Both types are used to answer geographic questions and provide a complete understanding of spatial phenomena.
- Key questions:
- What is happening where?
- Why is it happening there?
- Why does it matter?
- Uses of geospatial data: Applied in government services, disaster response, business, and personal decision-making.
Key Spatial Concepts
- Absolute location: The exact position of a place, given by latitude/longitude or a physical address.
- Relative location: Where a place is in relation to another, using cardinal directions (N, S, E, W), distance, or time. Always involves at least two places.
- Space: The unchanging, blank area of Earth's surface, serving as the setting for human and physical activity.
- Place: The physical and human characteristics that define a location, which can change over time.
- Site: The physical characteristics of a place, such as terrain, climate, and resources.
- Situation: The relationship between a site and other places, including accessibility and connections.
- Location theory: Explains why places are organized in certain ways and why they are located where they are.
- Connectivity and accessibility: How places are linked and how easily they can be reached, influencing movement and interaction.
- Centrality: The functional dominance or importance of a city within an urban system, often serving as a hub for activity.
- Flows: Patterns of movement from one place to another, including people, goods, and information.
- Distance decay: The decrease in interaction as distance increases, also known as the friction of distance.
- Time-space compression: When technology reduces the effects of distance, making places feel closer and increasing the speed of interaction.
- Land use: How land is utilized by humans, including agriculture, industry, and settlement.
- Cultural landscape: All human-made or altered features on the environment, reflecting cultural practices and values.
Human-Environment Interaction
- Modification: Changing the environment to meet human needs, such as building dams, roads, or cities.
- Adaptation: Adjusting human behavior and practices to fit environmental conditions, like wearing appropriate clothing or building on stilts in flood-prone areas.
- Environmental determinism: The idea that the environment shapes human activity and culture, limiting what people can do.
- Possibilism: The belief that technology allows humans to overcome environmental limitations and create new possibilities, making almost anything possible.
Key Terms & Definitions
- Thematic map: A map showing the pattern of a single phenomenon or data set.
- Choropleth map: Uses colors or shading to indicate values and show spatial patterns.
- Isoline map: Connects points of equal value with lines, useful for showing elevation or temperature.
- Cartogram: Distorts area size to represent data intensity, making regions larger or smaller based on the data.
- GIS: A system for combining map layers for analysis and answering geographic questions.
- GPS: A satellite-based system for determining precise location anywhere on Earth.
- Absolute location: The exact coordinates or address of a place.
- Relative location: The position of a place compared to another, using direction, distance, or time.
- Time-space compression: Technology reducing the impact of distance on travel and communication, making the world feel smaller.
Action Items / Next Steps
- Review and study examples of each map type and projection to understand their uses and limitations.
- Practice identifying different map projections and their characteristics, noting how each distorts shape, size, or distance.
- Read more about how GIS and GPS function and explore their real-world applications in mapping and analysis.
- Complete assigned practice questions on geographic concepts and spatial analysis to reinforce understanding.
- Explore how geospatial data is used in government, disaster response, business, and personal decision-making, and consider examples of each.
- Use visual aids such as charts, graphs, and satellite images to enhance understanding of spatial patterns and geographic data.