GPS

Networks Providing GPS GNSS

NAVSTAR (US)
GLONASS from Russia
BeiDou / COMPASS from China’s
Galileo from Europe (As of December 2017, 22 of the planned 30 active satellites are in orbit.)

The bottom line is that there is no question of

GPS Accuracy https://www.gps.gov/systems/gps/performance/accuracy/
- Quote: "most of today's civilian devices use only one GPS frequency, while military receivers use two."

To specify a location based on coordinates in Google Maps, use (Name) loc:-24.4356,27.731626
- URL build: http://maps.google.com/maps?z=12&t=m&q=loc:38.9419+-78.3020
  - z=zoom
  - t=type, ("m" map, "k" satellite, "h" hybrid, "p" terrain, "e" GoogleEarth)
  - q=search query (prefixed by loc: then google assumes it is a lat lon separated by a +)
  - e.g. http://maps.google.com/maps?z=12&t=h&q=loc:-26.194707+28.279794&
Google Picasa client can upload/backup photos to web, Google maps photo's with embedded GPS coords.
Rough script to covert .csv commadelimited file to google .mkv csvtokml-20100330.py

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