At 2010-09-07 02:57, Nathan Edgars II wrote:
So obviously this is a tower:
http://commons.wikimedia.org/wiki/File:Electric_transmission_lines.jpg
I use a key of tower_type with the following values to specify the type of
tower when they are not one of the "normal" types (for which I could not
easily come up with names).
This is one example what I call a "normal" single-circuit (3-phase) type:
http://sites.google.com/site/am909geo/osm-1/power_1.jpg
This and your example above are what I call a "normal" dual-circuit
(3-phase) type: http://sites.google.com/site/am909geo/osm-1/power_2.jpg
and this is a pole (no matter what voltage it carries):
http://commons.wikimedia.org/wiki/File:Pyl%C3%B4ne_haute_tension.JPG
I use tower_type=monopole for your example and this one:
http://sites.google.com/site/am909geo/osm-1/power_monopole.jpg
But what about something like this, where there are several poles with
crossbars:
http://commons.wikimedia.org/wiki/File:Electric_power_transmission_-_Ljusdal.JPG
I treat this just as my other "normal" non-monopole single-circuit towers.
When you look at them, they are all made from various kinds of structural
members, including poles, angle-iron, etc. I suppose it might be useful to
identify the ones with wood in them for weather/fire reasons. Maybe
material=wood?
Or this, where a single pole is made of metal with diagonals:
http://commons.wikimedia.org/wiki/File:Stork_nest_on_power_mast.jpg
It doesn't look like a single pole. It looks like multiple pieces of tubing
with supporting angle-iron pieces. I'd treat it like a normal dual-circuit
tower.
I also have these:
tower_type=dipole :
http://sites.google.com/site/am909geo/osm-1/power_dipole.jpg Two solid
metal/concrete poles that meet (or almost) near the top. dual-circuit capacity.
tower_type=u_frame :
http://sites.google.com/site/am909geo/osm-1/power_u_frame.jpg Forms a
continuous upside-down U. Multiple sections can be joined sideways,
resembling "ladyfingers", to handle more than 2 circuits. (This example is
unusual in that it only carries a single circuit, with one phase on the
right circuit position and the other 2 phases on the left circuit position).
tower_type=a_frame :
http://sites.google.com/site/am909geo/osm-1/power_a_frame.jpg Usually seen
as the input and output interfaces of a substation. The example shows two
of them at right angles to each other. They are made of two identical
A-shaped structures with a single pole across the apex of them, similar to
a sawhorse. The insulators are spaced evenly across that pole between the
A-shaped sides. Additional structures are added sideways to accommodate
more circuits.
tower_type=a_frame :
http://sites.google.com/site/am909geo/osm-1/power_a_frame_wide.jpg This
type of structure is used to carry more than 2 medium-voltage circuits down
a utility corridor. Similar to the a-frame described above, it has two ends
with tower sections across them. In this structure however, the three
phases of a circuit are aligned vertically instead of horizontally. They
can be made quite wide to accommodate more circuits horizontally (I've seen 9).
To each, I add circuits=* to indicate the number of circuits the tower can
handle (not necessarily how many are currently strung on it, which is
specified in power=line + cables=*). The number of cables per circuit is
implied by the type of transmission, with the default of 3-phase
high-voltage AC having space for 3 cables per circuit.
--
Alan Mintz <alan_mintz+...@earthlink.net>
_______________________________________________
Tagging mailing list
Tagging@openstreetmap.org
http://lists.openstreetmap.org/listinfo/tagging
