The method of systematic random sampling (METHOD=SYS) selects units at a fixed interval throughout the sampling frame or stratum after a random start. PROC SURVEYSELECT chooses the first unit randomly ...

Simple random sampling can be conducted by using ... that is based on shared characteristics and attributes. Systematic ...

If you specify the option METHOD=PPS_SYS, PROC SURVEYSELECT selects units by systematic random sampling with probability proportional to size. Systematic sampling selects units at a fixed interval ...

Key fact Most sampling is random, but systematic sampling can be used if there is a trend or pattern across the habitat, such as distance up a beach, or altitude on a hillside. If you are using ...

With systematic sampling you can then select the points to monitor but this can introduce bias. Random sampling eliminates bias by generating the points randomly. Now you need sampling tools.