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Fig. 6. Changes in the estimates of SOC (soil organic C) stocks using the median method for coarse-dispersed brown soils (soil family) as map scale decreases from 1:500 000 to 1:1 000 000. Arrows indicate the map generalization process as map scale decreased, and the two SOC stock values in each shaded box were based on some delineations of a map unit being preserved while others were merged into other map units during the map generalization process. For example, after the overlay analysis of the 1:500 000 and 1:1 000 000 soil maps using GIS (geographic information system) software, 12 337 km2 (293.50 Tg C/23.79 kg C m–2) of coarse-dispersed brown soils on the 1:500 000 scale soil map were preserved at the same locations of the 1:1 000 000 scale soil map; 3585 km2 (85.28 Tg C/23.79 kg C m–2) of coarse-dispersed brown soils on the 1:500 000 scale soil map were merged into delineations of diluvial brown soils, weakly developed brown soils, etc., on the 1:1 000 000 scale soil map; and 2631 km2 (62.59 Tg C/23.79 kg C m–2) of mountain prairie–meadow soils, dark-compacted brown soils, etc., on the 1:500 000 scale soil map were merged into coarse-dispersed brown soils on the 1:1 000 000 soil map during the map generalization process.
