%0 Research article
%T Weighting alternative estimates when using multi-source auxiliary data for forest inventory
%A Poso, Simo
%A Wang, Guangxing
%A Tuominen, Sakari
%D 1999
%J Silva Fennica
%V 33
%N 1
%R doi:10.14214/sf.669
%U https://silvafennica.fi/article/669
%X Five auxiliary data sources (Landsat TM, IRS-IC, digitized aerial  photographs, visual photo-interpretation and old forest compartment  information) applying three study areas and three estimators, two-phase  sampling with stratification, the k nearest neighbors and regression  estimator, were examined. Auxiliary data were given for a high number of  sample plots, which are here called first phase sample plots. The plots  were distributed using a systematic grid over the study areas. Some of  the plots were then measured in the field for the necessary ground  truth. Each auxiliary data source in combination with field sample  information was applied to produce a specific estimator for five forest  stand characteristics: mean diameter, mean height, age, basal area, and  volume of the growing stock. When five auxiliary data sources were used,  each stand characteristic and each first phase sample plot were  supplied with five alternative estimates with three alternative  estimators. Mean square errors were then calculated for each alternative  estimator using the cross validation method. The final estimates were  produced by weighting alternative estimates inversely according to the  mean square errors related to the corresponding estimator. The result  was better than the final estimate of any of the single estimators. The  improvement over the best single estimate, as measured in mean square  error, was 16.9% on average for all five forest stand characteristics.  The improvement was fairly equal for all five forest stand  characteristics. Only minor differences among the accuracies of the  three alternative estimators were recorded.