Geography 111:
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Geog 111 Lecture Outline: Portraying the Earth
Update: 7/27/05

Surface of earth of interest to geographers

Maps are a great tool to help understand and analyze the earth's surface


1. The Nature of Maps

Map: a two dimensional representation of the spatial distribution of selected phenomena; usually components of the human or physical landscape

A scaled drawing of a portion of a landscape, representing the area at reduced scale and showing only selected data

McKnight fig 2.1: Different kinds of maps

1a. A Matter of Scale

Map scale

Maps are almost always smaller than the portion of the Earth's surface they portray

Lewis Carroll "Sylvie and Bruno Concluded"

"What do you consider the largest map that would be really useful?"

"About six inches to the mile."

"Only six inches!" exclaimed Mein Herr. "We very soon got to six yards to the
mile. Then we tried a hundred yards to the mile. And then came the
grandest idea of all! We actually made a map of the country on a scale
of a mile to a mile!"

"Have you used it much?" I enquired.

"It has never been spread out, yet," said Mein Herr: "the farmers objected: they
said it would cover the whole country and shut out the sunlight! So we
now use the country itself, as its own map..."

Map Scale Types

Graphic scale: line or bar on map represents some set distance

Word scales: describes the scale of the map in words

Fractional scales: representative fraction: a proportion between map distance and Earth distance

Large and Small Scale Maps

McKnight fig 2.3: comparing map scales

Large scale / Small scale distinction is based on the representative fraction

1b. Map Graticule

Necessary to have a means of locating phenomena on the earth and on maps

McKnight fig 1.17: latitude / longitude

1c. Map Projections

Globes have the least distortion from the actual earth

Problem: have to flatten out the Earth to get it on a flat surface

Image courtesy of Lilla Locurto and Bill Outcault

Inevitable distortions occur when you project a map

Always some kind of distortion: of size, shapes, ...

McKnight fig 2.10: conformal vs equivalent map projections

1d. Map Generalization: using judgement in the elimination of detail and reduction of the number of features on the original map

Mark Monmonier: "Reality is three-dimensional, rich in detail, and far too factual to allow a complete yet uncluttered two-dimensional graphic scale model. Indeed a map that did not generalize would be useless." (How to Lie With Maps)

1e. Map Content: reference vs. thematic

reference maps: general use (for many purposes), focus on and emphasize the location of things in the environment - many different purposes; like a general world atlas or encyclopedia

thematic maps: particular use or theme: focus on and emphasize the spatial patterns of one or several human or environmental phenomenon

1f. Map Symbolization

symbol: A thing representing something else because of relationship, association, convention, or resemblance.

Special Map Symbol: Isolines

Basic characteristics of isolines

2. Developments in Mapping: Computer aided Mapping

2a. Global Positioning System (GPS)

McKnight fig 2.16: 24 satellites around Earth, transmitting positioning information back to earth

GPS Orbits

2b. Remote Sensing

Remote sensing: any measurement or acquisition of information by a recording device that is not in physical contact with the Earth's surface

Aerial Photographs

Multispectral Remote Sensing

Increasingly: remote sensing (airplane, satellite) sensors gather energy (passively, or actively) from different parts of the electromagnetic spectrum

2c. Geographic Information Systems: GIS

Computer hardware and software for the capture, storage, retrieval, analysis, and display of spatial data

GIS is basically digital maps linked to digital databases

McKnight fig 2.29: layers which can be linked together in a coordinate system (lat/long)


Six basic map attributes of all maps - paper or digital

Developments in mapping

Much more on all this stuff in Geography 222: The Power of Maps

E-mail: Geog 111 Main Page and Course Description krygier teaching page. krygier top page.

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