 # Mapping the Earth

• Things you should UNDERSTAND, KNOW, and be able to DO...

Understand:
• maps can be used to gain various kinds of information
• the 3-dimensional world is typically represented on 2-dimensional maps

Know:
• the Earth’s shape is an oblate spheroid
• lines connecting points of equal values on a map help us represent the 3-dimensional world
• the space between isolines represents a fixed value
• topographic maps represent landforms through the use of contour lines that are isolines connecting points of equal elevation.
• gradients and profiles can be determined from changes in elevation over a given distance.
• Earth’s coordinate system of latitude and longitude, with the equator and prime meridian as reference lines, is based upon Earth’s rotation and our observation of the Sun and stars.
• the altitude of Polaris depends on the latitude of the observer
• Earth rotates at 15 degrees per hour. Meridians of longitude are the basis for time zones.

Terms: axis, troposphere, lithosphere, hydrosphere, known elevation, contour interval, contour line, depression line, elevation, equator, gradient, oblate spheroid, isoline, field value, latitude, longitude, Polaris, pole, Prime Meridian, profile, time zone, topographic

Do:
• use Earth Science Reference Tables (ESRT) to gain information
• describe the composition of the Earth’s crust, hydrosphere and troposphere using the ESRT
• determine direction using a compass rose
• use data to draw isolines
• use a scale on a map to determine distance
• construct and interpret a topographic profile
• determine values of and between isolines
• calculate gradient using a topographic map and/or field values
• determine the direction of stream flow from a topographic map
• estimate maximum and minimum values on an isomap
• interpret and label depression contours (hatchure lines)
• determine the latitude and longitude of a given point to the nearest degree
• calculate local time based on longitude
• determine latitude by use of the star Polaris
• determine the angle from horizon to Polaris using an astrolabe and relates this to latitude