LECTURE DAY

Cartography & GIS

February 5, 2026 | Foundations of Spatial Science

Foundations

1. The Power of Projections

To map a 3D Earth onto a 2D surface, we must use Map Projections. This process inevitably introduces distortion in shape, area, distance, or direction.

Key Projection Families

  • Cylindrical: (e.g., Mercator) Preserves direction but distorts area at poles.
  • Conic: Ideal for mid-latitude regions like the United States.
  • Azimuthal: Preserves distance from a central point, often used for polar regions.
📖 Read eBook Ch. 1
Data Models

2. Vector vs. Raster

GIS represents the world in two primary ways: discrete objects (Vector) and continuous surfaces (Raster).

📐 Vector

Points, Lines, and Polygons. Precise boundaries. Best for urban planning, roads, and land parcels.

🖼️ Raster

A grid of pixels. Best for continuous data like temperature, elevation, or satellite imagery.

Review

Summary of Big Ideas

  • ✓ All Maps Lie: It is mathematically impossible to flatten a sphere without distortion. A cartographer's job is to choose the "useful lie."
  • ✓ Symbology is Language: How we symbolize data (colors, size, shape) dictates how the user interprets the "truth" of the map.

🎓 Cartography Quiz

1. Which projection family would you most likely use to map the contiguous United States?

Conic (e.g., Albers Equal Area)
Mercator
Polar Azimuthal

Lectures

Lecture 1: Cartography

Introduction to map design, projections, and symbology.

Lecture 2: Intro to GIS

The GIS components, data models, and spatial analysis basics.

📝 Key Concepts for the Exam

Cartographic Fundamentals
  • Map Projections: The mathematical transformation of the 3D Earth (Geoid/Ellipsoid) onto a 2D surface. All projections involve distortion (Shape, Area, Distance, or Direction).
  • Vector Data: Discrete representation of geographic features using Points, Lines, and Polygons.
  • Raster Data: Continuous representation of geographic data using a grid of pixels (e.g., satellite imagery, elevation).
  • Scale: The relationship between distance on a map and distance on the ground. Large-scale maps show small areas with high detail.
  • Symbology: The use of visual variables (color, size, shape, value) to represent data values on a map.