Cartography – Maps & Scale Youtube Lecture Handout

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Agenda

• Data and its types

• Map and Scale

• Analyzing Maps

To view sample questions and notes visit www.doorsteptutor.com

Types of Data

Idiographic vs. Nomothetic

Map

• Map is graphical representation of real world.

• Art of map making = Cartography

• Maps can be:

  • Reference or Base Maps: Show natural and human-made objects from geographical environment with an emphasis on location, atlas or topographic maps

  • Thematic Maps: Geographical distribution of one phenomenon or spatial associations that occur between a number of phenomena

    • Isopleth maps - Isolines connect points of equal magnitude.

    • Choropleth map - tonal shadings are graduated to represent areal variations in number or density within a region, usually a formal region.

Topographic Map

Thematic Maps

• Quantitative:

  • Choropleth: Color gradient

  • Chorochromatic: Various Color

  • Choroschematic: Symbols

  • Isopleth: Lines

  • Proportional Symbols: Size of symbols

  • Dot Density Maps: Population

• Qualitative

Why We Need Maps?

• To represent a larger area than we can see

• To show a phenomenon or process that is not visible by eyes

• To present information concisely

• To show spatial relationships

How to Prepare Maps?

• By actual survey

• By photographs

• By free sketches

• By Computer Maps

Elements of Scale Map

• Symbols and a legend

• Scale

• Direction (indicated by the north arrow)

• Map grid or coordinate system

• About the map (date created, title, author, source information)

Characteristics of Map

Reading Map is Indeed an Art!

• Maps are selective views of reality

• Size of the map relative to reality (scale)

• What’s on the map (symbolization)

• Shape of the map (projection)

Scale

• Scale is about distance.

• How long?

• How far?

• How wide?

• How far on the map and how far on the ground?

Map Scale

• Representative Fraction: Is a ratio like 1:1000

• Verbal Statement: 1:1,000,000 verbally is "1 centimeter on the map equals 10 kilometers on the Earth's surface"

• Graphic Scale

1:25,000 Scale

• 1 centimetre (cm) on map = 25,000 cm on the ground

• 1 cm on the map = 250 metres (m) on the ground

• 4 cm on the map = 1 kilometre (km) on the ground

Analyzing Map Scale

Types of Scale: Comparative Scale

Diagonal Scale

Vernier Scale

Time Scale

Reduction & Enlaargement

• After reducing a map from 1:10,000 to 1:50,000 scale, the new map is, the original line or scale & times the area.

• After enlarging a map from 1: 100,000 to 1: 20,000 scale, the new map is times the original line or scale & times the area of the original scale.

• If a map with scale 1: 100,000 is enlarged by 10 times the new scale can be calculated as follows. Assume that the new scale is , then, or , so & enlarged scale is .

Reduction/Enlargement by RF

When the map is enlarged the RF is decreased. E.g., if the original map with scale 10 cm = 5 km, is enlarged 4 times, the new RF will be 1:12500

Maps Based on Scale

• Cadastral or Revenue Maps: Large scale 16-20 inches to 1 mile

• Topographical Maps: Single purpose, 1 in = 1 mile

• Wall Maps: Depict Large Area 1 in = 4 miles

• Atlas Maps: Small-scale chorographical, 1:2000000

Map Symbols

• Symbols are a code instead of text

• Symbols can be

  • Point: Each symbol count as one occurrence

    • Qualitative: Explains location

    • Quantitative: Shows distribution

  • Line: One-dimensional for borders, roads etc.

  • Area: two-dimensional like garden, plot etc.

• Consider shape, size, orientation, pattern, color, value

-Manishika