1. Maps and photos - Chapter 8
All maps have common elements
Scale
Legend
Coordinate system
Orientation info

2. Scales
Verbal- words used to convey map distance / real world distance equivalencies
e.g., one inch equals four thousand feet
Graphic- usually a bar or line with calibration marks that indicate map distance real / world distance equivalencies
Fractional - the numeric unitless ratio of map distance real world distance equivalencies
1:40,000

3. Legend- a window that shows all the symbols used on the map, commonly includes scale, title, and orientation inforamtion

4. Coordinate systems
Latitude Longitude- based on 360 degree circle coordinate system with Equator and Prime meridian as the index lines
Commonly given as decimal degrees ( ° N, ° W), degrees with decimal minutes (38° 36.32’ N, 98° 18.2’ W) or degrees minutes and seconds (38° 36’ 18” N, 98° 18’ 12” W)
North
South

5. Coordinate systems
UTM- a coordinate system based on a 1000 meter grid with the center of of each zone as the alignment point of the grid cells
UTM coordinates might read 16 S E N

6. Coordinate systems
Township Range a coordinate system based on a numeric grid

7. Topographic maps
Contour lines represent vertical elevation with reference to sea level (zero elevation) they are isometric lines of what ever they are representing, in our case elevation
Contour intervals are 5, 10, 20, 50 or 100 foot intervals
Index contours are labeled and thicker
Contour lines never cross or touch
They “V” when they cross a stream channel, with the point of the “V” in the upstream direction
They can create closed shapes on the map
can represent either a hill or a depression
Frequently used to make topographic profiles

8. Real distance as determined from map (Km)
Aerial Photos
Frequently need to know the scale on stereo photos
Must compare to map with known scale
Photo distance (mm) =
Real distance as determined from map (Km)

9. Geological maps
Usually indicated by numerous colors used to identify various geological units
systems
groups
formations
members
Contacts are indicated by lines with varying degrees of certainty by solid or dashed lines
Also indicate location of geological structures
faults
folds
intrusions
dikes and sills