ExternalNodeId2ZLevels

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);