[Proj] help with clark66 as datum
pramsey at refractions.net
Fri Mar 10 00:47:44 EST 2006
I would assume that the "D_Clarke" stuff is just a mistake, and that
all they mean is a Clarke 1866 spheroid. Does this work?
+proj=merc +lon_0=100 +lat_ts=-46 +ellps=clrk66
On 3/9/06, Hamish <hamish_nospam at yahoo.com> wrote:
> I'm trying to figure out PROJ.4 parameters for a newly published
> dataset that has been widely distributed down here in New Zealand.
> ERSI Shapefile .prj file that came with it:
> Documentation that came with it:
> The projection used [...] is:
> Mercator Projection
> Central Meridian = 100
> Standard Parallel = -46
> False Easting = 0
> False Northing = 0
> Spheroid/Datum = Clarke 1866
> This confuses both me & the GRASS GIS projection auto-import tool.
> Does clark66 define a datum??
> Is this meaningful: DATUM["D_Clarke_1866", ??
> Should I give up and just assume +towgs84=0,0,0 ?
> I have no idea why they used clark66 or a point in the ocean 1500km SW
> of Perth Australia as the center of projection for a modern New
> dataset. But so it is.
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