On 19/11/2011 17:59, James E. Morrison wrote:
As I recall, about a year ago someone posted a Google Earth add-on to
make it easy to measure the declination angle of walls or buildings
with Google Earth. I don't even remember what it was called. I would
appreciate it if someone could point me to it.
Thanks,
Jim
James E. Morrison
[email protected] <mailto:[email protected]>
Astrolabe web site at http://astrolabes.org
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Hi Jim,
My recent attempts to measure a wall declination on a windy
hillside using my precision declinometer were defeated by a combination
of a VERY rough and irregular stone wall surface and a howling gale
which penetrated the Perspex draught screen around the sensitive
pendulum. This was overcome by the best compromise I could devise. The
ridgeline of the church roof was assumed to be perpendicular to the
front face of the building so a screen grab from Google Earth was
'placed' in Adobe Illustrator where a semi-transparent protractor I drew
for a different purpose some years ago measured the required angle. Of
course this assumes that True North is a vertical line in a Google Earth
view. As the stone dial, made by a subcontractor, is to be set into a
deep cavity in the rough stonework a little 'wedgeing' on installation
should compensate.
Any comparable drawing program should work this way.
Tony Moss
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