Fieldwork Flashcards
What is random sampling?
How would it be used in urban and coastal landscapes?
Random sampling is when you collect data by chance.
Eg. sediment sample and Questionnaires
Random sampling pros and cons
Advantage - Everything has an equal chance of being included in the study – a truly random sample will be more representative of the population
Disadvantage - when the sample set of the larger population is not inclusive enough, representation of the entire population is skewed by inaccurate data.
What is systematic sampling?
How would it be used in urban and coastal landscapes?
Locations and sites found at equal intervals.
Eg. beach profile and land use survey
Systematic sampling pros and cons
Advantages:
Reduces bias as results taken at equal intervals leading to accurate results.
Disadvantages:
Transect may exclude key sites.
Stratified sampling and pros and cons
Data taken in small areas in a larger case study which are different.
Ensures each subgroup in a population receives proper representation.
Requires prior knowledge of the area
Beach profile method
Person A stands near the edge of the sea with a ranging pole.
Person B stands further up the beach with a second ranging pole.
Measure the distance from each pole using a tape measure, and the angle of the beach using a clinometer.
Sediment angularity method
Decide your sampling strategy and place a quadrat at that point, picking up 10 pebbles.
Using powers index, measure the roundness of angularity of the pebble.
Complete this at each stage of your beach profile.
Rate of longshore drift method
Select your start and finish points and measure the distance using a tape measure.
Put orange in the water before the starting point and time how long it takes to travel the distance using a stopwatch.
Wave analysis method
Measure waves in a fixed time using a stopwatch eg. 1 or 2 minutes on each side of the beach
Put metre stick on the ocean floor and measure wave height on different sides of the beach.
