Local researchers and rangers believe that the environment and landscape of the high moor in the Kushiro wetlands have been changing. However, they do not have any maps which clearly show the evidence of these changes in terms of plant communities. In order to detect tiny signs of environmental changes, comparison of past and present aerial photos is useful. Aerial photos were taken in 1998 and 2010 using a nonmetric color film camera mounted on a balloon and a nonmetric digital camera mounted on a Cessna in the high moor area, Akanuma, Kushiro wetlands, respectively. Images were processed in digital form and classified using OBS (Object Based Segmentation) to map 40 types of wetland plant communities in fine scale. After revisions, the maps were compared to analyze changes in the plant communities. Significant change in the distribution of some plant communities was found.

The following conclusions were found.

a) While the natural successional sear of wetland plant communities had occurred, the retro successional sear had been widely occurring. This fact implies that the environment of this area has been changing to wetter conditions, since plant communities that favor wetter conditions or shallow water are apparently more prevalent in 2010 than in 1998.

b) High spatial resolution imagery of wetland is very useful to detect environmental change in terms of composition of plant communities.

Finally, better countermeasures for wetland environmental conservation could be applied in the early stages of environment change.

The textbook of error theory for the national licensed surveyor's examination has been used the standard deviation based on “Handbuch der Vermessungskunde” by Jordan (1895). This standard deviation is called “Der mittlere Fehler” and it is denoted by m＝√［ε²］/n, where ［　］ indicates summation, ε is an error and n is the number of measurements. In general, the standard deviation is defined by σ＝√E［(X－μ)²］, where X is a randum variable and μ＝E［X］. This paper studies on the historical error theory in Japan.