Cartography and Map Reading

Grid Systems

• A toposheet is divided into a grid system to facilitate location and measurement of distances
• Grid lines are spaced at regular intervals, usually 1 km or 1 mile apart
• Grid systems used in toposheets include:
  • Universal Transverse Mercator (UTM) system
  • Universal Polar Stereographic (UPS) system
  • State Plane Coordinate System (used in the United States)

Scale Representation

• Toposheets are drawn to a specific scale, which is the ratio of the distance on the map to the corresponding distance on the ground
• Scale is represented as a fraction (e.g. 1:25,000) or as a verbal statement (e.g. 1 inch = 1 mile)
• Toposheets can have different scales, such as:
  • Large-scale maps (e.g. 1:10,000) for detailed planning and navigation
  • Small-scale maps (e.g. 1:100,000) for general overview and planning

Contour Lines

• Contour lines are used to represent the relief of the terrain on a toposheet
• A contour line is an imaginary line on the map that connects points of equal elevation
• Contour lines have the following characteristics:
  • Closely spaced lines indicate steep slopes
  • Widely spaced lines indicate gentle slopes
  • Contour lines that form a "V" shape indicate a valley or depression
  • Contour lines that form a "U" shape indicate a ridge or hill

Grid Systems

• Grid systems are used in toposheets to facilitate location and measurement of distances
• Grid lines are spaced at regular intervals, usually 1 km or 1 mile apart
• Three common grid systems used in toposheets are: • Universal Transverse Mercator (UTM) system • Universal Polar Stereographic (UPS) system • State Plane Coordinate System (used in the United States)

Scale Representation

• Toposheets are drawn to a specific scale, which is the ratio of the distance on the map to the corresponding distance on the ground
• Scale can be represented as a fraction (e.g. 1:25,000) or as a verbal statement (e.g. 1 inch = 1 mile)
• Two types of scales used in toposheets are: • Large-scale maps (e.g. 1:10,000) for detailed planning and navigation • Small-scale maps (e.g. 1:100,000) for general overview and planning

Contour Lines

• Contour lines are used to represent the relief of the terrain on a toposheet
• A contour line connects points of equal elevation on the map
• Characteristics of contour lines: • Closely spaced lines indicate steep slopes • Widely spaced lines indicate gentle slopes • Contour lines that form a "V" shape indicate a valley or depression • Contour lines that form a "U" shape indicate a ridge or hill