%0 Research article
%T Generating a raster map presentation of a forest resource by solving a transportation problem
%A Muinonen, Eero
%D 2005
%J Silva Fennica
%V 39
%N 4
%R doi:10.14214/sf.368
%U https://silvafennica.fi/article/368
%X Necessary tools for raster map generation, for the approach based on the  calibration estimator, were developed and implemented. The allocation  of the area weight of each pixel to sample plots was formulated as a  transportation problem, using a spectral distance measure as a  transportation cost, and solved using the transportation simplex  algorithm. Pixel level accuracy was calculated for the methods based on  the calibration estimator so that the results could be compared with the  results of the nearest neighbour estimation, the reference sample plot  method (RSP) at pixel level. Local averaging in a 3 x 3 window was  performed for each generated raster map as a postprocessing phase to  smooth the map. Test plot results were calculated both for the  unfiltered raster map and the filtered raster map. RSP produced the  smallest RMSE in the pooled test data. Local averaging with a 3 x 3  filter decreased the pixel level error – and the bias – and the  differences between the methods are smaller. Without local averaging,  the pixel level errors of the methods based on solving the  transportation problem were high. Raster map generation using the  methods of this study forms an optional part – followed possibly by the  classification of the pixel level results – of the whole computation  task, when the area weight computation is based on the calibration  estimation. For larger areas than in the present study, such as  municipalities, the efficiency of the method based on the transportation  model must be improved before it is a usable tool, in practice, for  raster map generation. For nearest neighbour methods, the area size is  not such a problem, because the inventory area is processed pixel by  pixel.