Traffic Logix SafePace 100 3 Cell Battery, Руководство по установке

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Page 16 2011 Copyright Traffic Logix Corp. SafePace 100: Installation Manual Ver. 2.0
Appendix A – Determining True South
There are three ways to determine which way is true south.
Google Earth
You can use Google Earth to zero in on your house and find true south. This requires
downloading a small program from the Google Earth site. Place the item you want to determine
the direction of right in the center of the display, as the angles change as you pan around. In
the “View” drop ‐ down menu, selecting "Grid" will display a latitude ‐ longitude grid in which the
grid lines run in the north ‐ south and east ‐ west directions.
Solar Noon Method
This method uses the fact that the sun is always true south at solar noon. A shadow cast by a
vertical object at solar noon runs true north ‐ south. So, at solar noon, use the shadow cast by a
plumb ‐ bob string or the vertical edge of a building to determine true south.
To determine the local time that corresponds to solar noon, find the sunrise and sunset times
from a current local paper (where "local" and "current" are both important!). Most GPS units
will also give the times for sunset and sunrise ‐‐ just make sure the GPS is set to your time
zone. Solar noon is exactly half way between the sunrise and sunset time. Note that the
difference between local time noon and solar noon can be quite a bit, depending on your
location in the time zone, and daylight saving time.
You can also use this NOAA solar time calculator to find the local time for solar noon at your
location:
http://www.srrb.noaa.gov/highlights/sunrise/sunrise.html
This Print Solar Noon Calendar prints out solar noon for your exact location for the entire year.
East
South
West
Solar
Noon