Map Basics

Maps

An attempt to portray things that are distributed across space.

Map Creation1. Simplification – narrow down the criteria used in

order to produce a clear and uncluttered view of whatever it is the cartographer wants the map to show.

2. Classification - how a cartographer categorizes the data he or she wants to show on a map. (example: precipitation)

3. Symbolization - a cartographer takes data and renders it into symbols such as shapes, colors and patterns to portray it on the map.

4. Induction – estimation – it’s not always possible to have data for everyplace on the map.

Reading a Map

Scale - the size of an area - relationship between the distances on the map and the actual distances on Earth IMPORTANT – it can influence how things

appear. Map Scale portrayed in three ways.

1. Representative Fraction – ie: 1:100,000,0002. Written Statement / Verbal – one inch to

1,600 miles3. Graphic Scale / Bar Scale - represents a

segment of a ruler

Scale – Large or Small???

Depends on how much detail is needed. Large-scale Maps

Larger fraction more detail Smaller area

Small-scale Maps – smaller number, less detail . Smaller fractions Less detail Larger area

How To Read a Map Map Key – explains lines, symbols and colors

on a map. Dots: major cities or capitals Compass Rose – cardinal directions

Latitude Latitude – run west to east BUT measure

north and south parallel Varying lengths

longest: the equator, shortest: the poles

Thermal characteristics Low latitudes – 0-30o – warm all year, no distinct

seasonality Mid latitudes – 30 – 600 – distinct winter and

summer High latitudes – 60 – 90o – cold almost all year,

short “warm” season

Longitude

Longitude – run north and south – measure east to west

00 – Prime Meridian – Greenwich, England

1800 – international date line

Hemispheres

The Equator and and the Prime Meridian divide the earth into spheres.

The Equator - Northern and Southern Hemisphere

The Prime Meridian – Eastern and Western Hemisphere.

Map Projection A 3D surface to a flat surface. Distortion will occur in at least one area:

Area Direction Distance Shape

no "best" projection.

Types of Map Projections

The Globe Mercator

(Transverse, Oblique and Space Oblique)

Cylindrical Robinson Conic (Albers

Equal, Lambert Conformal, Equidistant (Simple Conic), Polyconic, Bipolar Oblique Conic Conformal

Sinusoidal Equal Area

Orthographic Stereographic Gnomonic Azimuthal

EquidistantLambert

Azimuthal Equal Area

Types Map Projections The Globe True: Directions, Distances, Shapes and Areas Great circles—The shortest distance between

any two points on the surface of the Earth can be found quickly and easily along a great circle.

Disadvantages: Even the largest globe has a very small scale

and shows relatively little detail. Costly to reproduce and update. Difficult to carry around and bulky to store.

Types Map Projections

Mercator

Types of Map Projections

Robinson

Types of Map Projections

Conic (Simple)

How Maps are Made

Today satellites are used to make maps. Geographic Information Systems (GIS) Maps are produced faster and are easily

changed.

General Purpose Maps

Maps that show a wide range of general information about an area.

Political – names and boundaries of cities and other human-made features of a place.

Physical - labels landforms and water features

Contour – shows elevation

Special Purpose Maps

Or Thematic Maps, which present specific kinds of information – themes or patterns. Climate Natural resources Population density Historic