Updated 2009 Sep 14
Each of the below regions uses variants of the NAD 83 reference frame and a local vertical datum. Several versions of NAD 83 exist conforming to significant plates: Pacific, Marianas, and North America. Likewise, each region has its own vertical datum. It is not possible to level across water, so islands will have selected a tide gage to serve as the local datum point and all leveling is tied to that site. The only exception to this is Hawaii. No tide gage was selected in the Hawaiian Islands. Hence, GEOID09 in Hawaii transforms between NAD 83 (PAC00) and the same geopotential (geoid) surface as the USGG2009 model (a gravimetric geoid surface).
Items that are listed in the below table include the final GPSBM files
for each region as both Excel spreadsheets and text files
as well as thumbnail images linked to larger images showing the
distribution of the GPSBM's. The island regions are smaller
and more consistent, so no significant points were dropped.
For CONUS, 1002 points were dropped based on the criteria given
in the rejection code:
'S' for State adviser requested (216 total),
'h' for excessive ellipsoidal height error for those
where it was available (970 total), and
'H' where the residual orthometric height was too large
with respect to neighboring points (16 total).
Even though over a thousand were rejected, over 19,443 were kept.
One other point was rejected because it fell physically
too close to another point for computation.
You can look at a image of the rejected CONUS points below.
GPS on BM - CONUS
GPS on BM - CONUS Rejected
GPS on BM - Alaska
GPS on BM - American Samoa
GPS on BM - Guam
GPS on BM - CNMI
|Excel Spreadsheet Files||GPSBM2009CU||GPSBM2009AK||GPSBM2009AS||GPSBM2009GM||GPSBM2009NM|
|Ellipsoidal Reference Frame||NAD83 (CORS96) 2002.0||NAD83 (CORS96) 2003.0||NAD83 (PACP00)||NAD83 (MARP00)||NAD83 (MARP00)|
NAVD88 - NORTH AMERICAN VERTICAL DATUM OF 1988
ASVD02 - AMERICAN SAMOA VERTICAL DATUM OF 2002
GUVD04 - GUAM VERTICAL DATUM OF 2004
NMVD03 - NORTHERN MARIANAS VERTICAL DATUM OF 2003
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