Transcript change in field value

FIELD VALUE
A field value is a measurement taken in the environment.
There are two types 1) scalar and 2) vector.
Scalar field values – are measurements that only describe magnitude
(how much – amount)
Examples – temperature
pressure
elevation
Vector field values – are measurements that describe both magnitude
and direction.
Examples – wind
gravity
Field Value Maps – isotherm temperature
isobar pressure
contour (topographic) elevation
Field values are plotted on a map according to the location that the
measurement was taken.
Field values that are the same number are then connected to each other to
create lines of equal value called isolines.
DO NOT CROSS LINES !!!!!!!!!!
Anywhere you are on that line the value will be the same.
See page 26 (fig 2-7)
Field values can change over time.
See reference table for gradient formula
Gradient = change in field value
change in distance
• What is the elevation of an area?
• Where is the steepest gradient?
The steepest gradient occurs where the contour lines are drawn closest
together.
• Where is the most gentle gradient?
The gentle gradient is where the contour lines are drawn farthest apart.
• What is the gradient of the Brigitte River from the 200 foot contour line to
the contour line before the Brigitte River meets the Newburgh River?
• Direction of Stream / River flow ?
Streams and rivers flow from an area of high elevation to an area of low
elevation. The contour lines bend towards the source (where it begins)
• Profile a side view that shows changes in elevation.
• Review book page 30
• study fig 2-9 on how to construct a profile.
TOPOGRAPHIC CONTOUR MAPS
See review book page 29 Callister Quadrangle
You must be able to answer the following !!!!!
1) Name of the location
2) Latitude /Longitude
3) Map Scale is used to measure distance
4) Map direction * = true north, MN = magnetic north
5) Symbols
6) Benchmark (BM “X”) is the recorded elevation of that area at the time of
placement.
7) Depression – an area on the map that represents a hole or valley
symbol for depression “comb marks”
Romano Swamp and Lerose Sink
8) Contour Interval – may or not be given describes how much the value of
each line changes