____ ___

What is a Field? Field – any area of space in which every point has a measurable quantity. Example: fall foliage, magnetism, gravity, elevation, precipitation, air pressure, wind, temperature, etc.

What are the lines on a field map? Isolines – are used to connect points of equal value on a field map. Isolines can appear as individual solid lines or as the boundary between different colors on a field map.

? Isotherms – connect equal temperatures. 50°F 55°F 50°F 60°F 50°F

Isobars – connect equal air pressure. Isobars are the white lines

Contour Lines – connect equal elevations.

Contour Interval – the difference in value between adjacent isolines. What is the contour interval? ________________ 50°F 10°F 50°F 60°F 50°F 60°F

Most fields are “Dynamic” Something that is dynamic changes over time. Example: Temperature constantly changes, so temperature maps are different every time you see them.

Some fields are “static” Something that is static does not change over time. Example: Gravity does not change, so the map will be the same every time you look at it.

Fields can also be scalar or vector. A Scalar field has magnitude only. (a number) Example: temperature is 830F A vector field has magnitude and direction. Example: wind is N at 10 knots

Why is there a need for field maps? Field maps provide us with a tool to view tons of numerical data in an easy-to-read format. Without field maps weather forecasting, construction, exploration, volcanic prediction, etc. would not be possible.

Rules for Drawing Isolines: USE A PENCIL ONLY. Connect points of equal value. Connect points with gentle curves, not straight lines. The isolines must go to the edge of the map, or form closed circles. Isolines can never touch or cross each other. The contour interval must be the same for the entire map.

Gradient is how steep the area is. steep gradient gentle gradient