SC120 Map Interpretation, Air Photos, and GPS

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Module 1 - Map Overview

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What is a map?

A graphical representation of surface features with components of scale and spatial locatioin.

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Why maps are important?

• General understanding of land locations.
• Specific data about geographic and cultural features on lands.
• More complicated problems such as road and dam building.
• Travel and navigation.

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Map Categories

• Base Map
  • Shows an outline for viewing other features.
  • Has only basic information, not much detail or information.
  • Used for initial overview of an area.
  • Provides a framework for developing thematic maps.
  • Mostly show the following natural and cultural features:
    - Water bodies
    - Town area
    - Parks
    - Highways, roads, railway.

• Thematic Map
  • Shows detailed information about a specific theme.
  • Thematic maps are prepared by superimposing thematic information on a base map.
  • These could be:
    - Forest cover
    - Land use
    - Agricultural
    - Soils
    - Geologic
    - Wildlife habitat
    - Climate
    - Population
    - Electoral

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Kinds of maps

• Geographic Map:
  • Displays the earth's surface, form and physical features, natural and political divisions, and climate.
  • Covers large areas, shows little spatial detail.
  • Map scale relatively small.
  • Example: Ecoregion map of Alberta at 1:1,000,000 scale.

• Topographic Map
  • Shows elevation and shapes of terrain features.
  • Covers smaller area than geographic map.
  • Shows more spatial detail, such as terrain, cultural features, vegetation.
  • Map scale relatively large.
  • Example: Topo map of Vermilion at 1:50,000 scale.

• Cadastral Map
  • Shows property and land ownership boundaries in urban areaas.
  • May show streets, lots, urban landscapes, utility plans, etc.
  • Map scale very high.
  • Example: Cadastral map at 1:5000 scale.

• Engineering Map
  • Shows engineering plans for constructioin of roadways, bridges, dams, etc.
  • These are specialty maps designed for construction purposes, not meant for general public.

• Hydrographic Map
  • Shows water bodies like lakes, ponds, rivers, streams, etc.
  • Shows drainage pattern of watersheds.
  • Shows depths of lakes and rivers.
  • Provides navigational charts.
  • Example: Bathymetric maps that show depths of water bodies.

• Geological Map
  • Shows subsurface geology such as faults and lineaments.
  • Shows subsurface profile useful for mining, engineering, etc.

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Map Elements or Components

• Map Sheet Title or Name (1): Example: Vermilion. Typically found in two places -- center of lower margin and right side of lower margin. Generally named after outstanding populated area.

• Map Sheet Number (2): Found in three places -- upper right and left corners, and lower right corner. Based on National Topographic System (NTS). Example: 72E/7.

• Scale (3): Shows how reduced the map features are. Shows the relationship between distance on the map and distance on the ground. Found in two places -- center of the bottom margin (ration and bar scale) and upper margin on the left side.

• Edition Number (4): Shown in upper margin on the right side and in the lower right corner.

• Legend: Used for interpreting the symbols on a map. On topographic map, it's usually on the back.

• Credit Note or Author (5): Could be government organizations, private companies, etc. On the bottom left. Also called imprint.

• Data Sources (5): Origin of geographic and thematic data. Sources could be: aerial photo, satellite imagery, field surveys.

• Map Production Date (5): Could show map composition date, printing date (edition), date of data sources (e.g., date of aerial photo), date of cultural check.

• Adjoining Maps Diagram (6): Adjoining maps of NTS. Found on the bottom right margin.

• Grid Reference Box (7): Contains instructions for composing a grid reference. On the right margin, above the adjoining maps diagram.

• Declination Diagram (8): On the right margin, above the grid reference box. Shows angular relationships among true north, grid north, and magnetic north.

• Feet to Meter Conversion Scale (9): On the right margin, above declination diagram.

• NATO Box (10): Top right margin. Small box containing the military series and sheet number of the sheet.

• Conventional Signs (11): Signs of roads, tracks, trails given in the bottom margin onthe left side.

• Contour Interval (12): Bottom margon on the rigfht side.

• Projection and Datum (13): Immediately below the contour interval.

• Border or neatline: Border containing all geographic features.

• Geographic Coordinate Information: Spatial coordinates such as: UTM, DLS, Lat/Long, Plane.

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