Thank you. But do not believe that I am able to understand the data.

Look at the resulting 30 lines, when you execute the following query for the 'Sonnblick'-trail of Topo Austria v3:

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1) You will see equal values of 'org_node_id' and 'dst_node_id', although the listed coordinates are different?

2) Furthermore 30 segments are listed with 31 different points. That's ok and my first thought was, that these segments can be linked together. But taking a closer look at the segments you will only find 28 different starting and 29 different final points. So it can't be a linked list of these segments.

3) No, there is a maximum of 19 segments, which can be linked together. You will find them in the following lines:

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And there are also four shorter possibilities to link segments, but you can't link them together with other parts:

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4) And why are starting points in the segments of lines 12 and 13, of lines 21 and 22 and the final points in lines 9 and 20 equal?

But be sure that all listed segments belong to this trail, which I was hiking this summer.