(7) + (8) + (9) Maps Flashcards
(29 cards)
1
Q
Types of maps
A
- Planimetric
- Topographic
- Thematic
2
Q
Planimetric
A
2D view of the earth from above
3
Q
Topographic
A
- 3D shape of earth’s surface from above
- Use contour lines (equal elevation) to show topology
- May also include planimetric map features
4
Q
Thematic
A
- Highlights some particular information
- Geologic maps (Distribution of rocks units, Soil types, Natural hazards, Groundwater information)
5
Q
All maps have a ___ to compare size on earth to the size on the map
A
Scale
6
Q
Scale Types
A
- Fractional Scale
- Graphic Scale
- Verbal Scale
7
Q
Fractional Scale
A
- Ratio
- Actual distance on the ground on the map between any two points
- Common scales (1:50 000) (1:20 000) (1:100 000) (1:250 000)
8
Q
Graphic Scale
A
- Line or bar indicated the relationship between the distance on the map and actual distance on the ground
9
Q
Verbal Scale
A
- Words express relationship
o 1 inch = 24 000 inches
10
Q
Directional Indicator
A
- North arrows
- Government topological maps: N is parallel to L and R sides of map
- But not the blue grid!
11
Q
Earth’s magnetic Pole
A
- Compasses point to it
- Earth’s magnetic pole is constantly changing in position
- Magnetic declination
o Angle (degrees, minutes, sec) between true N and magnetic N
o Adjust compass manually to account for magnetic declination
o Correction shown on government maps
12
Q
Finding Directions
A
- Indicate direction from one point to another
- Measuring in degrees
- Use protractor to measure from a map
- Use a compass to measure on the ground
- Express as azimuth or quadrant bearing
13
Q
Azimuth
A
- Number of degrees clockwise from north
- 000deg to 360deg
- Three-digit number
14
Q
Quadrant Bearing
A
- Four quadrants NE, NW, SE, SW
- Angle from North or South to East or West
- Acute angle
15
Q
Must know how to express Latitude and longitude, UTM, and public land survey co-ordinates
A
:)
16
Q
Latitude and Longitude
A
- Angular distances
- Latitude – distances N and S of equator (Equator = 0deg)
- Longitude – distances E and W of prime meridian (Prime meridian = 0deg)
- Equator and PM define the hemispheres of the world
- Express to the nearest second
17
Q
Universal Transverse Mercator system
A
- World divided into 60 zones, each 6deg
- Width changes in polar regions
- Measured in meters
- Each square on blue grid on topological map is 1 km by 1km (Offset from geographic and magnetic north’s)
18
Q
Public Land Survey
A
- Dominion Land survey
- Township-Range system
- Canadian Prairies and parts of BC and US use this
- Seven N-S meridians
- E-W baselines (49th parallel = 1st baseline, each one 24 miles)
19
Q
Division in PLS
A
- Townships (36 square miles) numbered from meridians and baselines (NS for TS, and EW for R)
- Sections (36 sections, each 1 square mile)
- Quarter Sections (4 Q-S in each section - NE, NW, SE, SW)
20
Q
Order of writing in PLS
A
- Quarter section – section – township – range – direction from meridian – meridian
- SW-20-12-9W4
- SW1/4, sect. 20, T12 R9 W4
21
Q
Topographic map colours
A
- Blue: water
- Green: vegetation
- White: no vegetation (can have grass)
- Black: cultural features (buildings, etc.)
- Brown: elevation (contour lines)
- Legend on back of topo maps
22
Q
Contour Lines
A
- Shows elevation
- Closely spaced contours: steep slope
- Widely spaced contours: gentle slope
- Evenly spaced contours: uniform slope
- Not all contour lines are labelled
23
Q
Hachure lines
A
- Small lines facing inwards on a circle
- Indicate a depression
- Can be on a contour line
24
Q
Spot Elevations
A
- Points with known measured elevation
- Benchmark
- Denoted with a dot or X plus a number (elevation)
25
Determining slope of gradient
- Amount of inclination of a surface or line with respect to the horizontal (rise/run)
- Expressed verbally (m/km, ft/mi)
- Expressed as a percent
26
Run: straight line distance or curved distance?
- Pay attention to what was asked
- “along a creek”: curved distance
- “from point A to point B”: straight line
27
Relief
- Difference between elevation of highest point and elevation of lowest point in the area
- When drawing topographic profile, use relief to scale the vertical axis
28
Vertical exaggeration
- Profiles are often exaggerated for the better emphasis
o Usually vertical scale is exaggerated cf. horizontal scale
- Expressed as a ratio
29
Look for on aerial photos to identify features
- Shape
- Size
- Tone
- Patterns (spatial arrangements)
- Shadow
- Topographic location
- Textures (smooth, coarse)