[GRASSLIST:1703] Re: v.proj bug?

Hamish hamish_nospam at yahoo.com
Fri Nov 7 03:09:25 EST 2003

> I have a raster dataset in the old New Zealand South Island grid 
> (Transverse Mercator: central meridian 171.5E, latitude of origin 44S,
> scale 1, false easting 500000, false northing 500000, units yards, 
> ellipse international). This projection is included in ArcMAP and when
> I compare a graticuled map in ArcMAP to (coarse scaled) printed grid
> of the raster  for the dataset, there is a very close match.

I have this definintion (from "concord"):

SNAT "South Island National Grid (yards)" REF_FRAME NZGD1949 &
          PROJECTION TM 171.5 -44 1.00000 500000.0 500000.0 0.91439841 &
          RANGE 0 0 800000 1000000

No time to look into this right now, but you might compare against what
"concord" gives: [runs fine under wine]


That "should" give a correct answer....

** Check if you are using the correct parameters for the NZGD49 datum:
[use GRASS 5.3+]


nzgd49 "New_Zealand_Geodetic_Datum_1949" international dx=54.4  dy=-20.1  dz=183.1

nzgd49 "nadgrids=nzgd2kgrid0005.gsb" "New Zealand" "LINZ NZGD49 NTv2 Distortion Model, accuracy 10-30cm"

nzgd49 "towgs84=59.47,-5.04,187.44,0.47,-0.1,1.024,-4.5993" "New Zealand" "Accuracy approx. 4m"

I'll get around to looking into this at some point, but can't now.

Curious to know what the data is & where it's from..

(way way down on the South Island, New Zealand)

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