Robert F. Sutherland
Mon Dec 10 19:22:17 EST 2007
I've been experimenting with Google Earth, once I realized that
the satellite images do generally have resolution sufficient
to show radio / TV towers! (and non-broadcast towers)
The critical touch is knowing where to look (from FCC coords),
and adjusting "eye altitude",
generally less then 5000' before towers are even visable,
and order of 1000' give a decent view.
Towers are not modeled as 3D objects.(yet?)....
only buildings, generally in large cities.
Good uses are to confirm array layouts, locations,
and FCC flawed coordinates. ("there's no such thing" uh huh)
Google Earth coordinate readings generally have a small difference
from USGS maps, longitude worse (a few seconds), maybe varible.
I have not sufficiently correlated the difference
to offer any ideas of prediction.
Tower shots are generally laid down, meaning viewed at an angle,
not on straight-up (down) view).
Seeing a tower's shadow helps a lot in reading location.
There is a lens effect, circular distortion,
(seen when move area (by clicking on "hand")
so don't trust distances exactly.
Commonly a marker is included, usually the studio/offices,
likely not the tower site.
Don't expect satellite images to be very recent,
but WUNR site 42:17:20,71:11:22 appears to show 5(7) towers,
thus the new construction!
Resolution depends on the quality of satellite image,
apparently subject to what an individual state has funded.
MA in general is very good resolution (Boston - very good),
Springfield - ok. N of Springfield, Mt.Tom - can't see the towers,
Pittsfield - ok, Worcester - ok (WTAG excellent)
NY: Albany area (including the Helderbergs with WRBG 6, etc)
has markers / labels of towers site, but detail is
totally insufficient to show any tower.
NYC is excellent resolution, ie the WCBS-WFAN tower on
High Island 40:51:35,73:47:09 at a eye altitude of 500'.
Phily, Baltimore, DC, Atlanta - very good.
Generally I screen-save images (via Paint Shop Pro) as a jpg,
but some, too much detail is lost,
a gif is necessary (but huge, ie 350kb)
3D models of buildings, I find, confuse locating towers in
a city due to simple models of buildings.
Thus image doesn't show tower on that building
(which "flat file" image does show).
To turn off 3D buildings, use left control column,
find "Layers", uncheck "3D buildings" box.
WROL, which the FCC coordinates, 42:26:15,70:59:40
has long-term been a difference from USGS map, ("WRYT")
Google Earth pinned it solid to agree with USGS.
An interesting view is DC's WDCW 50 38:57:44, 77:01:36
a curious --wide-- legged self-standing tower.
DC's WDCA 20 38:57:49,770618 very difficult to understand,
all I see is a white ghost.
Los Angeles's Mount Wilson (ie KABC-TV 34:13:37,118:03:58)
very good detail, even tho towers appear pointing upside-down.
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