[Gdal-dev] FW: TIGER not lining up?

[Frank Warmerdam]

On 6/23/05, Ben Discoe <ben at vterrain.org> wrote:
> Frank,
> I tried GDAL (OGR actually) on the Hawaiian TIGER2000 dataset, and it also
> gets the Datum wrong (NAD83, not OHD).  Should be a quick fix?

Ben,

I had no idea that there were non-NAD83 TIGER products!   Reading
section page 2 of chapter 5 of the 2002 TIGER/Line product manual 
I see that:

 In the 1995 and later TIGER/Line files, NAD83 is the coordinate datum
 used for the 48 contiguous states, the District of Columbia, Alaska, Puerto
 Rico, and the Virgin Islands of the United States. Regional datums are
 used for Hawaii and the Pacific Island Areas. NAD27 was the coordinate
 datum used for the 1994 and earlier versions of the TIGER/Line files
 except in Hawaii and the Pacific Island Areas where regional datums were
 used. Because the datum used was not relevant to the U.S. Census 
 Bureau's purposes for creating maps, the documentation did not record
 the specific datum of our source material for Hawaii and the Pacific Island 
 Areas.

So, it seems that the product doesn't internally document the datum but
that I could impute that OHD should be used if the STATE code is for
Hawaii.  Can you point me to a Hawaii file I could use for testing? 

Is OHD the "Old Hawaiian Datum" - EPSG code 4135?  This seems to
be the only specific Hawaiian datum listed in the EPSG 6.5 database. 

Best regards,
-- 
---------------------------------------+--------------------------------------
I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent