median of the strata definition ranges. This improvement is maintained after manual
editing is conducted in the hybrid stratifications.
Further, after the automated stratification process is applied, the majority of
stratum level standard deviations, based on percent cultivation, are significantly
lower when compared with the traditional area frames. The standard deviation
improvements for 25 out of 31 strata in the nine area frames indicate that utilizing
the automated stratification method significantly improves stratum homogeneity.
Manual PSU editing and review retains the improved stratum homogeneity
provided by the automated results, except in the low cultivation areas (stratum 40),
where the standard deviations are slightly higher in the hybrid frames. While
maintaining significantly improved levels of stratum homogeneity, the most significant impact of manual editing and review is an average 18% improvement in area
frame accuracy that directly results from the manual procedures. The combined
accuracy improvements based on the use of automated stratification and manual
editing/ and review results in significantly improved area frame accuracies for NASS
operational use.
Fig. 14.13 Nebraska traditional (top), automated (center), and hybrid (bottom) area frame
stratifications
294
C. G. Boryan and Z. Yang
editing is conducted in the hybrid stratifications.
Further, after the automated stratification process is applied, the majority of
stratum level standard deviations, based on percent cultivation, are significantly
lower when compared with the traditional area frames. The standard deviation
improvements for 25 out of 31 strata in the nine area frames indicate that utilizing
the automated stratification method significantly improves stratum homogeneity.
Manual PSU editing and review retains the improved stratum homogeneity
provided by the automated results, except in the low cultivation areas (stratum 40),
where the standard deviations are slightly higher in the hybrid frames. While
maintaining significantly improved levels of stratum homogeneity, the most significant impact of manual editing and review is an average 18% improvement in area
frame accuracy that directly results from the manual procedures. The combined
accuracy improvements based on the use of automated stratification and manual
editing/ and review results in significantly improved area frame accuracies for NASS
operational use.
Fig. 14.13 Nebraska traditional (top), automated (center), and hybrid (bottom) area frame
stratifications
294
C. G. Boryan and Z. Yang