Dynamic Data Linking and Programmability

ful for diagrammatic planning, such as designing harvest and silvicultural blocks, and as a geographic sketchpad for note-taking in the course o f planning activities. The SBWDSS could use this functionality in an ArcView version o f one o f its tools known as the Protection Planning System (PROPS), which is currently implemented using ARC/INFO. This system produces a thematic forest stand map shaded according to the priority it has for receiving protection against spruce budworm, calculated as the timber supply benefit (m 3 /ha) o f protecting the stand at the scheduled time o f harvest. Essentially, it is the additional volume gained if the stand is protected. The planner could use the information on this map to assist in drawing spray blocks for an aerial insecticide program, using the ArcView drawing capabilities. During this activity, the planner would attempt to create blocks that include the highest priority stands, given the constraints of the aerial application procedure. The geographic analysis capabilities o f ArcView allow examination o f relationships between themes, using theme-on-theme operations like point-in-polygon, line-inpolygon, and polygon-on-polygon. For example, to create a spruce budworm susceptibility rating, one could overlay the two previous years o f defoliation, budworm population data from egg-mass collections in the current year, and the spruce-fir stands from the forest inventory. With the spatial join capabilities o f ArcView, data that refer to the same geographic location, even if they were at different scales, could be joined to determine relationships that might otherwise be difficult to find. Aerial defoliation themes for the past ten years could be joined to an ecological zone theme, allowing comparison o f historic insect activity among different zones. Areas o f interest arising out o f this analysis could then be selected and converted into new themes (either temporary or permanent), and further compared with other information such as current vegetation. Spatial analyses like this are typical applications for GIS, but normally require significant software expertise and programming o f a specific procedure using the appropriate commands. This can be completed in ArcView in much less time, using the point-and-click user interface. In addition, simple proximity analysis can find relationships between two sets o f features, based on proximity. For example, displaying mature and overmature spruce-fir stands within a given distance o f other spruce-fir stands might identify clusters o f budworm susceptible forest.