Assume that you have now identified the population that you want information about. You now need to work out how to obtain samples from that population. There are a wide range of different sampling techniques that are chosen based on:

• ease of access to the sample,
• how representative (ie. free from bias) the sample is of the population, or
• a combination of the above.

We will first consider the traditional sampling techniques which do not account for any spatial distribution of the population. Then we will examine spatial sampling techniques that are based on the spatial variation of the population.

3.1 Traditional sampling
3.2 Spatial sampling
3.3 Spatial sampling methods

More information

You will be able to find more information on sampling methods from many statistical and data analysis books as well as on the web.

One such example is the Environmental Sampling and Monitor Primer.