[Liblas-devel] Re: GetProj4() string and NAD83

[Adam Stylinski]

On Tue, Jan 10, 2012 at 12:01 PM, Howard Butler <hobu.inc at gmail.com> wrote:

>
> On Jan 10, 2012, at 10:30 AM, Howard Butler wrote:
> > I'll try to dig into this some more...
>
> GDAL isn't turning this into a proper proj.4 string.
>
> >      GTModelTypeGeoKey (Short,1): ModelTypeProjected
> >       GTCitationGeoKey (Ascii,14): "UTM zone 15N"
> >       GeogGeodeticDatumGeoKey (Short,1): Datum_North_American_Datum_1983
> >       GeogEllipsoidGeoKey (Short,1): Ellipse_GRS_1980
> >       ProjectedCSTypeGeoKey (Short,1): PCS_NAD83_UTM_zone_15N
> >       ProjCoordTransGeoKey (Short,1): CT_TransverseMercator
> >       ProjLinearUnitsGeoKey (Short,1): Linear_Meter
> >       VerticalCSTypeGeoKey (Short,1):
> VertCS_North_American_Vertical_Datum_1988
> >       VerticalCitationGeoKey (Ascii,19): "GEOID 2003 Applied"
> >       VerticalUnitsGeoKey (Short,1): Linear_Meter
>
> is coming out of GDAL as:
>
> > +proj=tmerc +lat_0=0 +lon_0=0 +k=1 +x_0=0 +y_0=0 +datum=NAD83 +units=m
> +geoidgrids=g2003conus.gtx,g2003alaska.gtx,g2003h01.gtx,g2003p01.gtx
> +vunits=m +no_defs
>
> note the parameters, they're all 0.
>
> I don't know whether or not this is a bad set (or incompletely specified)
> of GeoTIFF keys, or whether or not GDAL should be taking the
> ProjectedCSTypeGeoKey straight off, as this defines the coordinate system
> parameters fully via lookup.  Frank, are you still around?
>
> Howard_______________________________________________
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> Liblas-devel at lists.osgeo.org
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>
>
(sorry, keep forgetting to CC the list on this).

I should note that it's not only these files, it seems to be any that use
anything other than WGS84.

For example, http://liblas.org/samples/test.las gives me issues (returning
what looks like HUGE_VAL).
And
http://data.capcog.org/Information_Clearinghouse/data/LiDAR/Fayetteville-SWB2.lasseems
to put me in the middle of the ocean.
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