Mapwork Flashcards
List 4 Characteristics of a Orthophoto map
1:10000
Black & white aerial photo
More detail
Contour interval 5m
What is a map?
A reduced version of reality
What are grid references?
Points of intersection between lines of latitude and longitude
What is scale?
How many times reality has been reduced
What map features does this Mapcode represent:
2930CB
29 degrees longitude(N or S)
30 degrees Latitude(E or W)
Big block C
Small block B
How do you work out distance?
100 000
What is the formula for area and what are the steps to work it out?
Formula -> A = L x B
Steps:
- Convert measurements to Km
- Input values into the formula
List 4 characteristics of a topographical map
1:50000
Colour
Physical features
Contour interval 20m
List 3 ways scale is shown on a map
- Ratio scale
- Linear scale
- Word scale
How do you work out gradient?
G = H
—–
D
Gradient = Difference in height/Distance between the points
Steps:
- Work out D, measure and convert distance to Kilometers
- Convert the kilometers into meters by multiplying by 1000
- Work out H by working out the difference in heights between the 2 points.
- Then fill in the equation and divide both the H & D by the H, to get a 1:something ratio
How do you work out true bearing?
Steps:
- Draw a North to South line, making sure the object is in the centre
- Then draw a line from the inject to the other object
- Measure the angle with a protractor
How do you work out Magnetic bearing?
MB = True bearing + Magnetic declination
Steps:
First workout True bearing
- Draw a North to South line, making sure the object is in the centre
- Then draw a line from the inject to the other object
- Measure the angle with a protractor
Then add the MD, remember that it cannot be more than 360 degrees(Start from 0 again)
What is Altitude?
The height above sea level
List 4 ways altitude is shown
- Contour lines
- Spot heights
- Trig beacons
- Benchmarks(roads only)
What do contour lines far apart represent?
A gentle slope