Mapping the Earth

 

• maps can be used to gain various kinds of information

• the 3-dimensional world is typically represented on 2-dimensional maps

 

• 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

 

• 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

• 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