[talk-au] answers to difficult questions

David Murn davey at incanberra.com.au
Sat Feb 20 04:11:33 GMT 2010


On Sat, 2010-02-20 at 05:16 +1100, John Henderson wrote:
> David Murn wrote:
> 
> > Ive laid out powerlines across most of the ACT and Queanbeyan, so feel
> > free to do the line from the wind farm to the Queanbeyan sub-station.
> 
> As well as the ways (power=line), shouldn't we be tagging the individual 
> nodes (pylons) also (power=tower), as is done here:

I toyed with that idea when I first started tracing them, but theres two
things to consider.  Main lines are generally tagged as power=line
whereas suburban lines are tagged as power=minor_line.  Main lines
generally use towers and cross large areas of land, where minor lines
often cross through areas already full of street data.

Ive been tagging all nodes as power=tower where its evident from nearmap
that there is a large metal tower, however rendered tiles only show the
power=tower nodes, not the power=pylon nodes.  I figured I was best off
doing the line tracing then if renderers support it at a later date, its
not too difficult to change the node to power=pylon.  When I create the
ways, I go from pylon to pylon, with no in-between nodes, so can depend
on every node that isnt labelled as power=tower being a pylon.

I havent seen many power lines drawn for Australia, but since they are
relatively easy to trace on nearmap and can be useful when shown on maps
at high zoom levels, I figured Id trace them in.  Ive also traced a
large number of powerlines from the Shepparton Nearmap, using the same
method described above.

David





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