[postgis-users] Linemerge roads

[Peter]

Stephen Woodbridge wrote:
>This is a tough problem I think because presumably it is a little more complex than stated.
>I assume that the real problem looks more like this:
>
>                     A
>                     |
>                     |
>I----------J---K------B--C----N
>            \ /          |
>             L           |
>             |           D
>             |
>             M

Yes the overall layer contains many crossroads and other types of intersections but im linemerging based on an id that is shared by each unique road, hence the normal intersections arent an issue its just that there are a small subset of these little short roadlets, that have the same id and name, where the road meets another road in a fashion like this:

|
|
|\
| C-------B-----A------
|/
|
|

so ignoring the upright road which has another id and name, the MULTILINESTRING has one id and contains 5 parts (all called say Breen Rd), the three on the right are changes from sealed to unsealed and the 2 angle ones are what im calling the Y ends) They are only 50m long or so. The reality is i have zero interest in the Y ends, id be happy to just prune them so i can join the rest and mid interpolate for the road label point.

Very interesting answer BTW! I can tell im going to learnt alot  here :)

Peter