Function Join(maxlength: single; filename: string): integer;
Join locates which links in a network can be joined together. If a node has only two links connected to it, that node may be superfluous for some purposes (aka. a pseudo-node). For other purposes it is needed, e.g. if you want to calculate the distance from that node to another or if the name of street or any other attribute change at that position.
Route calculations on a network with many pseudo nodes is slower and requires more RAM than the same one without pseudo nodes. This is the main reason for removing and compacting a network.
If a network has many very short links, which you would like to join, you can specify that links should be joined until they reach a length of maxlength. If maxlength=0, there is no upper limit and all links between nodes with more or less than 2 links, will be connected.
If a filename is specified (including full path), it should for each link contain a line with the street name. This can be used to stop the joins every time the street name changes on the links. If the file isn't found, the calculation is done as if the filename is "". The file can of course hold any string value.
The result can be saved using ResultSaveLink / ResultGetLink. All links with the same value>0 should then be joined/combined in a GIS-program. Now you can create a new topological network, which is smaller and faster.
Use OnJoinProgress event for tracking progress.
See also Join2.
Possible error codes: -10 -40 -41 -43
Versions: Pro
ActiveX / VCL / CLX component: RWcalc