Cartographer’s decisions …is about trying to find the best way to communicate with maps, depending on the purpose of the map and its intended audience

Cartographers hold the pen. One who makes maps Cartographers hold the pen.

Map making today Cutting edge technology helps cartographers make maps these days.

Remote Sensing the scanning of the earth by satellite or high-flying aircraft in order to obtain information about it.

Landsat The Landsat program is the longest running enterprise for acquisition of satellite imagery of Earth. On July 23, 1972

GOES The Geostationary Operational Environmental Satellite system (GOES) supports weather forecasting, severe storm tracking, and meteorology research.

GPS The Global Positioning System (GPS) is a space-based navigation system that provides location and time information in all conditions anywhere on or near the Earth’s surface.

GIS A geographic information system (GIS) is a system designed to capture, store, manipulate, analyze, manage, and present all types of spatial or geographical data.

What type of map projection should be used? The globe is the only true representation of Earth. The globe is the best representation of the earth. Distortions occur as the earth’s surface is flattened. A map projection is a way of drawing the Earth’s surface by presenting a round earth on a flat surface.

What type of map projection should be used? All maps are distortions of reality. The map shown is a Mercator Projection. This was once the most common projection. Notice how large Greenland and Antarctica are.

What type of map projection should be used? How much and what type of distortion should be allowed? Dots show how cartographers show distortion.

What type of map projection should be used? How much and what type of distortion should be allowed? Size (“Equal area” maps show correct size BUT shape may be distorted) Equal area maps show true size but shape may be distorted. Sometimes distance is distorted as well.

What type of map projection should be used? How much and what type of distortion should be allowed? Shape (“Conformal” maps show correct shape BUT size is distorted) But….Size is distorted

What type of map projection should be used? How much and what type of distortion should be allowed? -Shortest distance (Azimuthal maps show earth so that a line from the center point to any other point gives the shortest distance) But size and shape are distorted.

What type of map projection should be used? How much and what type of distortion should be allowed? Distance (“Equdistant” maps show correct distance.) But size and shape are distorted.

What type of map projection should be used? How much and what type of distortion should be allowed? In order to get accuracy in one area, you have to give up accuracy in another.

Physical Map

Political Map

What type of map should be used? Reference maps (general purpose maps with physical and human features) What to label? What names to use?

What type of map should be used? Thematic maps highlight a specific feature. Ex: Isoline maps connects points of equal value to make lines on a map

What type of map should be used? Thematic maps Ex: Choropleth maps uses shading to show variables. 2008 Election

What type of map should be used? Thematic maps Ex: Choropleth maps (by county)

What type of map should be used? Thematic maps Choropleth maps

What type of map should be used? Pin dot -each dot represents an occurrence

What type of map should be used? Cartograms: show show size using data other than area

Isoline maps connects points of equal value to make lines on a map

Flow line maps show movement of objects from location to location.

How much detail is needed? What to include and what to leave out… Geographers decide what scale to use by determining how much detail to show.

Large scale shows small areas in greater detail

Small scale maps show large areas in less detail

Key / Legend

Compass Rose / Cardinal Directions

How much detail is needed How much detail is needed? The scale of a map is the ratio of a distance on the map to the corresponding distance on the ground.

How much detail is needed? Scale--ways of showing scale Representative fraction (1/5,000) Verbal scale (1 inch equals 1 mile) Graphic scale (a line or bar on a map)

Representative fraction – 1/50,000 or 1:50,000 A ratio scale shows the ratio of distance on a map compared to its real earth measurement. A bar scale (graphic scale) shows the ratio of distance on earth.

Verbal scale – 1in. = 1 mile

Graphic scale – black and white line

What type of map should be used? Proportional symbol – uses a symbol to show frequency or intensity of variable Both maps show the number of mobile telephone Subscribers in 2003.

If Dr. Snow had used a choropleth map… Tracking Disease

All the cartographer did was change the scale All the cartographer did was change the scale. How does this change our perception?

What is important to understand about this? Knowing the decisions that cartographers make can help us to evaluate maps more effectively as we use them to understand our world.