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sci.geo.satellitenav (Global Satellite Navigation) (sci.geo.satellitenav) Discussion of global navigation satellite systems (GNSS). Topics include the technical aspects of GNSS operation, user experiences in the use of GNSS, information regarding GNSS products and discussion of GNSS policy (such as GPS selective availability). 

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#1




Part 2: Nightmare on GIS Street – Accuracy, Datums, and Geospatial Data
Part 2: Nightmare on GIS Street – Accuracy, Datums, and Geospatial Data
http://geospatialsolutions.com/part...ospatialdata/ 
#2




Part 2: Nightmare on GIS Street – Accuracy, Datums, and Geospatial Data
On 2013.05.23 19:00 , Sam Wormley wrote:
Part 2: Nightmare on GIS Street – Accuracy, Datums, and Geospatial Data http://geospatialsolutions.com/part...ospatialdata/ Good article.  "A Canadian is someone who knows how to have sex in a canoe." Pierre Berton 
#3




Part 2: Nightmare on GIS Street – Accuracy, Datums, and Geospatial Data
On May 24, 12:00Â*am, Sam Wormley wrote:
Part 2: Nightmare on GIS Street â€“ Accuracy, Datums, and Geospatial Data http://geospatialsolutions.com/part...streetaccura... Tell me Sam,how many times does the Earth rotate ,to the nearest full rotation,in proportion to the 4 times it makes an orbital circuit of the Sun ?. These satnav bozos concerned with 'accuracy will give the Earth 4 phantom rotations over 4 years which makes it impossible to apply rotation to plate tectonics which requires a maximum equatorial speed of 1037.5 miles per hour at the Equator.Want to see a real nightmare  "The angular speed of Earth's rotation in inertial space is (7.2921150 Â± 0.0000001) Ã—10âˆ’5 radians per SI second (mean solar second). Multiplying by (180Â°/Ï€ radians)Ã—(86,400 seconds/mean solar day) yields 360.9856Â°/mean solar day, indicating that Earth rotates more than 360Â° relative to the fixed stars in one solar day. Earth's movement along its nearly circular orbit while it is rotating once around its axis requires that Earth rotate slightly more than once relative to the fixed stars before the mean Sun can pass overhead again, even though it rotates only once (360Â°) relative to the mean Sun. Multiplying the value in rad/s by Earth's equatorial radius of 6,378,137 m (WGS84 ellipsoid) (factors of 2Ï€ radians needed by both cancel) yields an equatorial speed of 465.1 m/s, 1,674.4 km/h or 1,040.4 mi/h. Some sources state that Earth's equatorial speed is slightly less, or 1,669.8 km/h.This is obtained by dividing Earth's equatorial circumference by 24 hours. However, the use of only one circumference unwittingly implies only one rotation in inertial space, so the corresponding time unit must be a sidereal hour. This is confirmed by multiplying by the number of sidereal days in one mean solar day, 1.002 737 909 350 795,which yields the equatorial speed in mean solar hours given above of 1040 miles per hour ". http://en.wikipedia.org/wiki/Earth_rotation You poor,poor people  had you followed the proper astronomical principles where rotations/orbital circuits transfer loosely into days/ years and thereby stuck to the 24 AM/PM system in tandem with the Lat/ Long system a mess like this would never have occurred and researchers would be discussing the uneven rotational gradient of the fluid interior between equatorial and polar latitudes which is crucial for bind the spherical deviation of the planet with plate tectonics through differential rotation. 
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