Analysis of rodents and pests damage spot in Erdos City grasslands based on GIS

Application of geographic information system(GIS)instead of manual handing achieves mass geospatial information storage and processing, can help complete the inquiry and retrieval of spatial information and attribute information quickly and easily. In space information, it was necessary to analyze the figure spot area of grassland with pests and rodents for graphics data processing the area. It was useful to draw the region of rodents and pests of all banners and districts, and calculate the area on figure in order to monitor grassland pests and rodents. Area distribution of pests and rodents has been drawn using software in the grassland station of Erdos City since 2009. The original frame of axes were converted into degree format based on the data collected from banners and districts. The distribution map on pests and rodents of Erdos was achieved after topology processing of data imported in layer, however, the precision of the control point was very lower which resulted in that the calculating area was not in accordance with actual reported area. The error of pest damage area was as high as 37% and the error of serious damage area was 6%. The error of rodents hazard area and serious damage area were 48% and 41%, respectively. Banners of calculating area overpassed real area included Etuoke Banner, Wushen Banner, Ejin Horo Banner, and Dongsheng District after revising control points out of boundary, repeating calculation and comparing the modifying area. The range out of mainly concentrated area and the overlap of two figures area resulted in repeated calculation which deviated from the measured area consequently. The estatimated area closed to the real measured area after modification by figure spot partition calculation which reduces the generation of error area.