Spatial Sampling Designs - Sampling Spatial Units for Agricultural Surveys - page 190

Fig. 7.10 Semivariograms of the ANC variable within each of the four strata

Table 7.5 Relative efficiency of the sample mean (MSE/MSE SRS ) for each design, estimated
using 10,000 replicated samples from the EMAP lakes population, for different sample sizes, with
and without spatial stratification

Not spatially stratified Spatially stratified

Design n ¼ 10 n ¼ 50 n ¼ 100 n ¼ 10 n ¼ 50 n ¼ 100

SRS 1.00 1.00 1.00 0.52 0.77 0.82

GRTS 0.90 0.83 0.79 0.47 0.75 0.80

CUBE 1 0.95 0.99 0.93 0.47 0.74 0.76

CUBE 2 0.95 0.97 0.91 0.45 0.61 0.62

DUST 1 1.16 1.63 1.72 0.37 0.57 0.63

DUST 2 1.08 1.45 1.39 0.39 0.53 0.66

SCPS 0.80 0.66 0.56 0.44 0.56 0.53

LPM 1 0.75 0.62 0.46 0.42 0.47 0.45

LPM 2 0.81 0.67 0.54 0.48 0.58 0.54