1. Maps
Township and Range

2. Key Terms Map: a flat representation of a globe
Cartography - the art and science of mapmaking

3. SCALE
Scale: the relationship between units on the map and actual distance on the ground
Verbal Scale: one inch equals one mile
Linear Scale: | | | |
or Graphic Scale
Representative Fraction: 1:63,360

5. Latitude & Distance Earth’s Circumference 24,840 miles
24,840 divided by 360 degrees of a circle
One degree equals 69 miles
One degree can be divided into 60 parts or minutes
69 miles divided by 60 equals 1.15 miles
Therefore one minute equals 1.15 miles
One minute is a nautical mile (1.15 miles)

6. Latitude & Distance One minute can be further divided into 60 seconds
One minute or 1.15 miles divided by 60 equals 102 feet
Therefore one second equals 102 feet
WHAT IS THE DISTANCE SHOWN ON A 15 MINUTE MAP?

7. Map Projections
Projection: The system used to transfer locations from Earth’s surface to a flat map.
A projection of an image onto another surface
either a cylinder, a flat plane or a cone
3 basic types of projections
cylindrical projection
planular projection (also known as azimuthal)
conical projection

8. The Mercator projection has straight meridians and parallels that intersect at right angles. Scale is true at the equator or at two standard parallels equidistant from the equator. The projection is often used for marine navigation because all straight lines on the map are lines of constant azimuth.

9. CYLINDRICAL PROJECTION
used by navigators to show direction
Meridians run north & south
Parallels run east & west
Distortion on a Mercator map increases at an increasing rate as one moves toward higher latitudes.

10. Cylindrical Maps
are conformal maps

12. used for Mid-Latitude Maps
CONICAL PROJECTION
used for Mid-Latitude Maps
True Area (between the standard parallels)
Also referred to as equal area maps

14. PLANULAR PROJECTION
used by pilots
Shows Great Circle Routes

15. ROBINSON PROJECTION
Compromise projection

16. Robinson projection.
Robinson projection. This projection was developed to show the entire Earth with less distortion of area. However, this feature requires a tradeoff in terms of inaccurate map direction and distance.

17. This projection is common in maps that require somewhat accurate representation of area. This map projection was originally developed for Rand McNally and Company in 1961.

19. Magnetic North
The earth holds a mass of liquid, fluid mass of iron around the solid inner core
This generates a powerful magnetic field within the earth that is generated into outer space

20. True North = Geographic North
or North Pole
Magnetic North = where
the compass points to
76N W

22. Declination - the difference
between magnetic and
geographic north
17 E

24. X 100 = To calculate a percent slope Divide the change elevation (ft)
by the distance covered
change elevation (ft) | X
100 =
Average slope
distance covered

25. Township and Range System
The Township and Range system, sometimes called the Public Lands Survey System, was developed to help parcel out western lands as the country expanded.
The system takes many western states and divides them up using a base line and a principal meridian.
This system divides the land up into townships and ranges that are 36 square miles each.

26. Terms: Base Line: The horizontal line where the survey began.
Meridian: The vertical line where the survey began. Washington and Oregon are on the Willamette Meridian.
Range: The measure of township squares east or west of the meridian.
Section: A square mile numbered between 1 and 36 containing 640 acres.
Township: A six by six mile square containing 23,040 acres divided into 36 sections. Also used for the measure of township squares north or south of the base line.

27. Township and Range System
In the diagram, the square with the X in it would be defined as township 2 south (T.2S), range 3 east (R.3E). Each township and range is then subdivided into 36 sections.
Each section is one mile square. Individual sections are then subdivided into half sections and quarter sections and so on.
In the map below you can see sections 23, 24, 26 and 25 of T.22N, R.7E.

28. Township & Range Public Land Survey System
A rectangular grid system adjusted to the geographic grid
East west lines are surveyed and coincide with parallels of latitude
prominent parallel is known as the base line
Vertical divisions are called ranges
prominent meridians are called principal meridians

29. Township & Range Public Land Survey System
Basic unit is the township
Approximately 6 miles square
36 sections of one square mile
Plus allowances for road access
Sections
640 acres, more or less
4 quarters, 160 acres, more or less
16 legal subdivisions (lsds), 40 acres

32. Sections in a Township

33. Layout of Townships Began along 49th parallel of Latitude
10 Miles W of junction of Red and Pembina Rivers (Longitude 97 degrees, 27 minutes West)
E-W rows called Townships
N-S columns called Ranges