Unification and Harmonization in True Color Image City Map

True color image city map is a sort of new-style map which combines the high resolution image and map symbols and shows both advantages in visualization. At the same time, the map unification and harmonization should be taken into account dur-ing the design process, since some visual conflicts appear when map symbols overlaid on the true color image. The objective of this research is to explore the rules in the process of true color image city map design based on chromatic and aesthetic knowledge. At the end, taking the Image Atlas of Guangzhou as an example, image color adjustment, road network presentation, and symbol de-signing issues will be discussed in the application.

comCharacteristics of browsed aspen forests following wildfire and implications for management:a case study

Aims Recognizing ungulate browsing thresholds between viable and declining aspen(Populus tremuloides Michx.)stands are critical to ensuring long-term persistence of this biologically important plant community.Studies have shown declines in vigor and regeneration when as few as 30%of current annual twigs are browsed while other studies have shown higher limits.Although the effects of ungulate herbivory are of concern in aspen forests,few studies have assessed browsing effects following wildfire and few criteria exist for deter-mining potential effects of ungulate browsing on aspen forests fol-lowing wildfire.We evaluated the effects of ungulate abundance and foraging intensity on regenerating aspen 1 to 6 years post-fire and assessed the use of abundance and foraging intensity indicators in predicting impacts to regenerating aspen.Rocky Mountain elk(Cervus elaphus nelson)was the primary ungulate in the study area.Methods The study area was located within the 17500 ha cerro Grande Fire burn area in the Jemez Mountains,New Mexico,USA.We used percent aspen twigs browsed and pellet-group counts to evaluate relationships between these indicators and aspen patch structure(height,size).We collected data in randomly generated 3×33 m plots 5-6 years post-fire.We also established 4 fenced exclosures(25×55 m and 3.3 m in height)with paired unfenced plots 1-year post-fire to monitor aspen regeneration.Each spring,we recorded percent browsed twigs from the previous fall through the early spring period which coincided with the highest ungulate use period within the study area.We assessed associations between percent twigs browsed and pellet-group density and patch size and height of aspen using Spearman’s correlation coefficients.Important Findings Mean percent twigs browsed and ungulate pellet-group density across the burn area was≤31%and 1 pellet-group 100 sq m−1,respectively.Patch size and height decreased with increasing browsing and pellet-group density 5-6 years post-fire.However,mean aspen heights were approaching or exceeding a minimum browsing level of 2 m and,therefore,ungulate browsing did not appear sufficient to cause signif-icant impacts to aspen across the burn area.We observed a positive correlation between pellet-group density and twig browsing suggest-ing that one or both measures could be used to assess potential effects of browsing on regenerating aspen following fire.

An automated method for mapping physical soil and water conservation structures on cultivated land using GIS and remote sensing techniques

An efficient and reliable automated model that can map physical Soil and Water Conservation(SWC) structures on cultivated land was developed using very high spatial resolution imagery obtained from Google Earth and Arc GIS?ERDAS IMAGINE?and SDC Morphology Toolbox for MATLAB and statistical techniques. The model was developed using the following procedures:(1) a high-pass spatial filter algorithm was applied to detect linear features,(2) morphological processing was used to remove unwanted linear features,(3) the raster format was vectorized,(4) the vectorized linear features were split per hectare(ha) and each line was then classified according to its compass directionand(5) the sum of all vector lengths per class of direction per ha was calculated. Finallythe direction class with the greatest length was selected from each ha to predict the physical SWC structures. The model was calibrated and validated on the Ethiopian Highlands. The model correctly mapped 80% of the existing structures. The developed model was then tested at different sites with different topography. The results show that the developed model is feasible for automated mapping of physical SWC structures. Thereforethe model is useful for predicting and mapping physical SWC structures areas across diverse areas.