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Map - Types of Maps -Characteristics of maps

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Map

Definition: A map is a graphic form, normally to scale, of spatial abstraction of features on, or in relation to, the surface of the Earth. Urban Planning, Town Planning and Zoning through Geographic Information Systems

Types of maps

  1. Topographic maps
  2. Thematic maps

Topographic map:

A reference tool, showing the outlines of selected natural and man-made features of the Earth. ? "Topography" refers to the shape of the surface, represented by contours and/or shading, but topographic maps also show roads and other prominent features.

Thematic map:

A tool to communicate geographical concepts such as

  • The distribution of population densities, climate, movement of goods, land use etc.
  • Line maps versus photo (image) map
  • 2D vs 3D maps

Characteristics of maps

  • Scale
  • Projection

Scale

The scale of a map is the ratio between distances on the map and corresponding distances in the real world, e.g., if a map has a scale of 1:50,000, then 1 cm on the map equals 50,000 cm or 0.5 km on the Earth's surface.

"Small scale" and "large scale" is often confused, e.g, 1:50,000 vs. 1:500,000

The scale controls not only how features are shown, but what features are shown, e.g., Engineering building: 0.2mm*50,000=10 m? Map projections. The Earth's surface is curved but as it must be shown on a flat sheet, some distortion is inevitable.

Projection

A projection is a method by which the curved surface of the earth is represented on a flat surface.

Numerous projections have been invented for various applications

  • ?Cartographic abstraction ?- Selection of the few features in the real world to include classification of selected features into groups (e.g., bridges, churches, railways)
  • Simplification of jagged lines (e.g., coastlines
  • Exaggeration of features to be included that are to small to show at the scale of the map Symbolization to represent the different classes of features chosen

Geographic (Geo-spatial) information

  1. Information about places on the earth
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