Papa-Bear-NYC Posted September 20, 2006 Share Posted September 20, 2006 A related question to my previous post: "VERTCON" is defined as on the NGS dsdata.txt as VERTCON = The NAVD 88 height was computed by applying the VERTCON shift value to the NGVD 29 height. (Rounded to 0 decimal places.)and here's the example they give: BW0768 DESIGNATION - 1 BOLT BW0768 PID - BW0768 BW0768 STATE/COUNTY- MS/ADAMS BW0768 USGS QUAD - NATCHEZ (1976) BW0768 BW0768 *CURRENT SURVEY CONTROL BW0768 ___________________________________________________________________ BW0768* NAD 83(1986)- 31 33 42. (N) 091 24 25. (W) SCALED BW0768* NAVD 88 - 59.70 (+/-2cm) 195.9 (feet) VERTCON BW0768 ___________________________________________________________________ BW0768 GEOID HEIGHT- -26.30 (meters) GEOID03 BW0768 BW0768 VERT ORDER - FIRST CLASS II (See Below) ... BW0768 BW0768.The NAVD 88 height was computed by applying the VERTCON shift value to BW0768.the NGVD 29 height (displayed under SUPERSEDED SURVEY CONTROL.) BW0768.The vertical order pertains to the NGVD 29 superseded value. ... BW0768 SUPERSEDED SURVEY CONTROL BW0768 BW0768 NGVD 29 (??/??/92) 59.696 (m) 195.85 (f) ADJ UNCH 1 2 When is it VERTCON and when is it ADJUSTED? What does this category imply about the vertical control prior to the VERTCON shift? Here's an old mark that was adjusted from the old value, not shifterd: KU0982 DESIGNATION - TIDAL 737 STA II 6 KU0982 PID - KU0982 KU0982 STATE/COUNTY- NY/QUEENS KU0982 USGS QUAD - FLUSHING (1979) KU0982 KU0982 *CURRENT SURVEY CONTROL KU0982 ___________________________________________________________________ KU0982* NAD 83(1986)- 40 47 41. (N) 073 46 54. (W) SCALED KU0982* NAVD 88 - 3.004 (meters) 9.86 (feet) ADJUSTED KU0982 ___________________________________________________________________ KU0982 GEOID HEIGHT- -31.32 (meters) GEOID03 KU0982 DYNAMIC HT - 3.003 (meters) 9.85 (feet) COMP KU0982 MODELED GRAV- 980,257.0 (mgal) NAVD 88 KU0982 KU0982 VERT ORDER - FIRST CLASS II KU0982 ... KU0982.The orthometric height was determined by differential leveling KU0982.and adjusted by the National Geodetic Survey in June 1991.. KU0982 ... KU0982 SUPERSEDED SURVEY CONTROL KU0982 KU0982 NGVD 29 (??/??/92) 3.331 (m) 10.93 (f) ADJ UNCH 1 2 I cannot see how the original pre-VERTCON value in the first example was controlled. They both say "ADJ UNCH" in the superceded control line. Can anyone explain. Quote Link to comment
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