ExternalNodeId2ZLevels |
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In most datasets Z-levels are used to describe when streets intersect at different levels such as with bridges.
However, some use external node numbers instead to indicate that a shared coordinate belongs at different levels.
In this example we have 6 links with these fromnode and tonode values: 1: 100 - 500 2: 200 - 500 3: 400 - 601 4: 500 - 600 5: 600 - 700 6: 601 - 800
As can be seen on the simplified map below, node 600 and 601 is really the same coordinate, but since the external node is different, they have different Z-levels.
200 400 | | | | | | 100 ----- 500 ----- 600 / 601 ----- 700 | | | 800
This method helps you translating from external node numbers to Z-levels for the links.
After you have imported and opened a network, create a text file like this: 100,500 200,500 400,601 500,600 600,700 601,800
After calling the function you will get an output file with pairwise Z-levels like this: 0,0 0,0 0,1 0,2 2,0 1,0
Once applied to your dataset, you can import it again, this time declaring Z during import.
Syntax: ExternalNodeId2ZLevels(InputFile, OutputFile: string; GF: TGISFormat);
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