The algorithm considers only the original orientation of the lines when finding the shortest path. The cost of each input line is specified by Forward Cost Attribute. The cost of each input line is set to the 2D length of the line. Orientation of the line is not considered. The values that result from Cost Type are summed for all input lines as they relate to the From-To line, and the shortest sum becomes the shortest-found path. Note: Multiple feature types and features from multiple datasets will not generally naturally occur in the correct order.Īs with many scenarios, testing different approaches in your workspace with your data is the only definitive way to identify performance gains. In this case, using Group By with When All Features Received may be the equivalent and simpler approach. Multiple streams of data could be almost impossible to sort into the correct order, since all features matching a Group By value need to arrive before any features (of any feature type or dataset) belonging to the next group.
Sorting becomes more difficult according to the number of data streams. If the data needs ordering, it can be sorted in the workspace (though the added processing overhead may negate any gains). Performance gains are most likely when the data is already sorted (or read using a SQL ORDER BY statement) since less work is required of FME. The second possible reason is potential performance gains. In this case, the structure dictates Group By usage - not performance considerations. The first is incoming data that is intended to be processed in groups (and is already so ordered). There are two typical reasons for using When Group Changes (Advanced). Any features with a negative cost will be output through the port. If a feature does not have the attribute specified in the Forward Cost Attribute or the Reverse Cost Attribute, a zero cost is used for the line. Only linear features with non-negative cost attribute values are allowed if the Cost Type is set to By One Attribute or By Two Attributes. Specify Snapping Type = End Point Snapping and Add Additional Vertex = NEVER. Input the From-To Line through the Candidate input port and use the same value for Snapping Tolerance. If ShortestPathFinder produces unexpected results, consider using AnchoredSnapper instead. Computes the shortest path of a line or lines containing a source and destination node in a network based on the length of the input or the cost (specified in an attribute) of each of the edges.
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