+EraSeek Posted January 19, 2003 Share Posted January 19, 2003 The standards are as follows: A-Order: 1 part in 10,000,000 B-Order: 1 part in 1,000,000 1st-Order: 1 part in 100,000 2nd-Order Class I: 1 part in 50,000 2nd-Order Class II: 1 part in 20,000 3rd-Order Class I: 1 part in 10,000 3rd-Order Class II: 1 part in 5,000 Translation of proportional accuracy to spatila accuracy gets confusing. These standards are the legacy of nearly 200 years worth of conventional (angle and distance -- line of sight) surveying methods and relate the accuracy as a function of distance. For example 1st-order, 1 part in 100,000 (1:100,000) means that the accuracy between any 2 points of will not be worse than 1 unit in 100,000 units -- e.g. 1 meter in 100,000 meters, 1 foot in 100,000 feet, 1 inch in 100,000 inches etc. Unfortunately there is no way to convert a proportional accuracy directly to a spatial accuracy - 1 foot, 1 meter, 1 cm etc. without performing a comprehensive national readjustment of the entire National network. This is being planned for about 2003 or 2004. Until then we will have to live with approximations. These values can be "estimated" as a function of each stations relationship to the local network as and would be consistent with differential GPS applications. A-Order: 3 cm (0.10 foot) B-Order: 5 cm (0.16 foot) 1st-Order: 10 cm (0.33 foot) 2nd-Order Class I: 20 cm (0.66 foot) 2nd-Order Class II: 30 cm (0.98 foot) 3rd-Order Class I: 50 cm (1.64 feet) 3rd-Order Class II: 1 meter (3.28 feet) Quote Link to comment
Cholo Posted January 20, 2003 Share Posted January 20, 2003 quote:Originally posted by EraSeek: Translation of proportional accuracy to spatila accuracy gets confusing. Yes, I'll agree with that. What little spa can I go to, with accuracy and non-confusion? Quote Link to comment
+GEO*Trailblazer 1 Posted January 21, 2003 Share Posted January 21, 2003 I wish that I had the Mind set you have to go into such depth in the accuracy aspect of the technology.I know the how,why, what, and where but can not get it down in a written form as you do so well here.And how that even holding the GPSr it will fluctuate,because of the slight elevation it is recordig while you are moving.The reason for setting it down to become a little more stable. When all else fails Geotry again. Quote Link to comment
+EraSeek Posted January 21, 2003 Author Share Posted January 21, 2003 Guess I should have said that I got the above from here: http://gpsinformation.net/main/ngs-accuracy.html I simply thought it was an interesting bit of info to mull over, and thought it worth passing on. Quote Link to comment
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