Mapping Earth Unit – Things to learn:
Vocabulary:
Latitude
Longitude
Field
Field value
Isobar
Contour line
Gradient
Profile
Prime Meridian
Equator
Isoline
Isotherm
Contour interval
Hachure line
Basic facts to know:
1.
“lat” = flat (latitude lines are horizontal); longitude are vertical
2.
latitude measures degrees north/south; longitude measures degrees east/west
3.
latitude lines to know: 0 o
= Equator, 90 o
= poles longitude lines to know: 0 o
= Prime Meridian, 180 o
= International Date Line
4.
Latitude numbers are on the right and left of a map, long. Numbers are on the top & bottom of a map.
5.
Polaris (North Star) is used to find out latitude in the Northern hemisphere.
6.
Altitude of Polaris is equal to the latitude of the person looking at Polaris.
7.
The sun appears to move through the sky at a rate of 15 degrees per hour.
8.
Every hour difference between local time and Greenwich Mean time represents 15 degrees of longitude.
9.
Times at west longitudes are earlier than GMT, east longitudes are later.
10.
Every point on an isoline has an equal value.
11.
Isotherms connect equal temperatures; isobars connect equal air pressures; contour lines connect equal elevations.
12.
Smaller and smaller circles inside each other on a topographic map represent a hill.
13.
Lines are closer together on a steep hill, far apart where it is flat.
14.
Contour lines bend uphill when they cross a stream. – so the water flows opposite the way the lines bend.
15.
The elevation of an ocean coastline is always zero.
16.
Depressions (holes in the ground) are shown with hachured lines.
Things you should be able to do:
1.
Be able to use the latitude and longitude markings on the NY state map on page 3 in the reference tables.
2.
Be able to use the latitude and longitude markings on the world map on page 5 in the reference tables.
3.
To find Polaris: Use the two end stars on the big dipper – these are the pointer stars, an arrow drawn from them upward will point to Polaris.
4.
Rules for drawing isolines:
Rule1: line can’t touch or cross (except contour lines at a cliff); rule
Rule2: lines can’t end in the middle of a map (must go off edge or form a closed loop);
Rule 3: Lines must be in numerical order (and the only points in between should belong there)
5.
To use the gradient equation: top of fraction – find the two points and subtract to find the change in field value; bottom of fraction use the scale on the map to find distance
(unless distance is just given to you)

6.
To find out the highest possible elevation of a hill - figure out what the next contour line would be – then subtract one.
7.
To figure out the contour interval - find two values – count the spaces between, then divide
8.
Use the scale of the map to determine distance. (I recommend the edge of a piece of paper.)
9.
To draw a profile: Use edge of sheet of paper – mark off all contour lines and their elevations, move the paper to the graph – put dots above each mark, connect the dots
– make a hill at the top of all hills. It is important to keep the spacing of your marks the same as the spacing of the contour lines, and keep the spacing of the dots the same as the spacing of your marks on the edge of the paper.