Cartography – Maps & Scale YouTube Lecture Handout

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Cartography – Maps & Scale YouTube Lecture Handout

Agenda

  • Data and its types
  • Map and Scale
  • Analyzing Maps

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Types of Data

Types of Data in Image

Idiographic vs. Nomothetic

Idiographic vs Nomothetic Image

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

Topographic Map Image

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

Characteristics of Map Image

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
Map Scale Image

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

Analyzing Map Scale Image

Types of Scale: Comparative Scale

Types of Scale Comparative Scale Image

Diagonal Scale

Diagonal Scale Image

Vernier Scale

Vernier Scale Image

Time Scale

Time Scale Image

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