[postgis-users] number all houses on branch roads first

[Stephen Woodbridge]

Opened an enhancement request to pgrouting:
https://github.com/pgRouting/pgrouting/issues/625

On 7/12/2016 9:56 PM, Stephen Woodbridge wrote:
> Sounds like you want a "graph" based on the road network topology like
> what is used in pgRouting. Then given the graph do a depth first
> traversal of the topology, labeling the edges as you go.
>
> If you build the graph topology (not the postgis topology), the you can
> probably write a recursive query to do the traversal and labeling. I
> think I would probably write a pgsql function(s) to traverse the graph
> and label the edges.
>
> Unfortunately, pgRouting does not have depth first search function built
> into it, hence the need to code one in pgsql.
>
> -Steve
>
> On 7/12/2016 5:16 PM, Dan Jacobson wrote:
>> I want to go down the (all unnamed) roads in my future mountain
>> community assigning house numbers every 50 meters.
>>
>>    50-100   170-200
>>     /         /
>> 1  / 107 147 /  213
>> +-+---+---+-+----+--240--main-road--
>> 2 48   \   168
>>         \
>>       120-140
>>
>> I stay on my main road, but whenever encountering a fork, first go
>> down it.
>> "Depth first pre-order ordered labeled rooted binary tree traversal
>> but with central path"?
>> http://math.stackexchange.com/questions/1856814/binary-tree-traversal-with-fixed-final-node
>>
>>
>> OK for PostGIS, given a few linestrings, I suppose I first (somehow)
>> connect them to form a network, then ride my virtual car down it. And
>> whenever my odometer reaches another 50m, make a mark on the centerline.
>> (Assume a strict binary tree (mountain roads with no 4-way junctions))
>> At each road junction I first choose a side road, and if already on a
>> side road, first choose the left road, before choosing the right road.
>> When backtracking turn off my odometer, until finally back on to my main
>> road.
>>
>> Holy smokes, sounds tough. Can I do this with PostGIS or should I go
>> back to GRASS or what?
>>
>> (I am thinking instead of using ST_OffsetCurve (previous project, thanks
>> Sandro) to put odd on the left even on the right, down the centerline
>> I'll just put odd numbers at 25, 75m, padded "1 ", and even at 50, 100m
>> reverse padded " 2".) These points and their labels are what I want
>> for output.
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>>
>
>
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