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Home , Cartogram, Mollweide projection

Distortion of

APHG What is a ?

• A map is a generalization or representation of the real world -Geoid: actual shape of the Earth which is round and oblate (slightly squashed) - Maps contain distortions: cannot represent the three-dimensional Earth on a flat surface without reconfiguration from correct shape/reality

Maps continue…

1) Map scale – most maps are smaller than the reality they represent & map scale tells us how much smaller; tells relationship between distance on map and distance on Earth’s surface 2) Map type – you can display the same on different types of maps ex. thematic, dot, cartogram, etc.

What is ratio scale?

• Ratio scale: ratio of map distance to Earth distance – 1:10,000 means that one inch on the map equals 10,000 inches on Earth’s surface, one centimeter represents 10,000 centimeters, one foot equals 10,000 feet. – Recall a small fractions has a large denominator so that 1:100,000 is smaller scale than 1:25,000. – A large-scale map depicts a small area with great detail. A small-scale map depicts a larger area with little detail. RATIO SCALE Which is the large-scale map?

What is verbal scale?

• Verbal scale – translates the representative fraction into words – One inch represents one mile conveys more meaning than 1:63,360 – Used little in places where people use metric system What is graphic scale?

• Graphic scale – is a simple bar scale that portrays distance on the map

What is a ?

• Map projection: the way we fit Earth’s three- dimensional surface onto a flat surface; distortion in either area, direction, distance or shape • Equal-area projections: portrays areas on the Earth’s surface in their true proportions but can distort shape • Conformal projections: retains correct shape of small areas; / cross at right angles and scale is the same in all directions at any point on the map Mercator Projection…

• Developed in 1569 by Gerardus Mercator as a navigation tool; ex. of conformal projection • The meridians are equally spaced, parallel vertical lines, and the latitude lines are parallel, horizontal straight lines, spaced farther and farther apart as their distance from the Equator increases • Shapes are correct for all areas, and map has correct directional relationships • Advantage: Direction and shape are accurate Disadvantage: Size is distorted increasingly to the north or south of Equator. Mollweide Projection

Mollweide Projection

• Create in 1800s by Karl B. Mollweide and is an example of an equal-area projection • Advantage: Accurate depiction of area • Disadvantage :distorts shapes

Robinson Projection

• Frequently used • Distorts both size and shape, but not too much

What are some different types of maps? • A depicts a single feature, for ex.: climate, population, landform, land use, etc. • Types of thematic maps: – Isoline (Isopleth) – connects points of equal value – Choropleth – puts features into classes and then maps classes for each region – Proportional symbol (Graduated circle) – size of the symbol corresponds to the magnitude of the mapped feature – Dot – each dot represents some frequency

MAP TYPES Isoline (isopleth) choropleth

Dot distribution

Graduated circle What type of map is this? What type of map? What type of map? What type of map? What is qualitative vs. quantitative qualities? • Qualitative: shows the distribution of a particular set of information; ex. map showing the distribution of U.S. national parks • Quantitative: show spatial characteristics of numerical data; ex. map showing population of California What are mental maps?

• Individual’s internal geographic understanding of a place (aka cognitive map)

What is a cartogram?

• A presentation of statistical data in geographical distribution on a map

This cartogram shows world population that is why China and India are more larger than the other nations… Cartograms exaggerate sizes based on statistical value of particular theme represented in map