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Streamlining processing-Building adjacency tables in batches
Applies to: Remsoft Spatial Planning System 3.27.
Date: 8/15/2004
One of the inputs for any spatial planning model is data indicating the location of objects in relation to other objects. In forestry, the forest resource is represented spatially as a composite of individual forest polygons.
The Remsoft Spatial Planning System generates spatial relationships among polygons by building pairwise lists of forest polygons that are within a user-specified distance of one another and stores them in dBase tables. I will refer to this user-specified distance as the proximal distance, and the associated polygon list as the adjacency table.
Adjacency tables are used in several applications in the System, in particular Stanley. If you anticipate the need to use different spatial relationships then you will need to generate an adjacency table for each. The purpose of this tech tip is to describe a method for generating multiple adjacency tables in a single process.
Normally, adjacency tables are built on an as-needed basis: anytime that you specify a proximal distance, if the associated adjacency table is not present, then the System will build it. This process, albeit intelligent, can take some time to complete, especially if the shapefile contains a large number of polygons and the distance is large. Once built, however, adjacency tables never need to be updated unless the shapes themselves change. Thus, from an efficiency standpoint, it makes sense to generate adjacency tables for all the potential distances that you might use at one time.
Rather than building adjacency tables on-demand, you can use the Build adjacency table utility to generate adjacency tables ahead of time.
To access the Build adjacency table utility, do the following:
1. Right-click the Maps view to display the context menu.
2. Mouse-over Spatial utilities.
3. Select Build adjacency tables from the sub-menu.
To add a distance to the build list, do one of the following:
• Click the Distance combo box down arrow and select a distance from the list.
• Type the distance into the Distance combo box directly and press Enter.
As you select or type distances, they are added to the build list. Once you have specified all of the desired distances, click Calculate to generate the associated adjacency tables. The System will build a separate adjacency table for each distance specified. As this process can take some time, it is usually advisable to run the build overnight or at a time when your PC is otherwise idle.
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