[gdal-dev] gdaltransform question

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[gdal-dev] gdaltransform question

McLane, Kathleen A ERDC-RDE-GRL-VA CIV
Hello,

I'm using gdaltransform to transform points from one datum to WGS84. In version 2.2.3 and 2.4.0 of GDAL, when I convert a point I receive a transformed latitude, longitude, and a new height value. In versions 2.4.1 and 3.0.1, when I convert a point I receive a transformed latitude and longitude but height always equals 0. Attached are examples of the height value issue. Is this a GDAL error, or am I doing something wrong?

Thank you,

Kathleen




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Re: gdaltransform question

Even Rouault-2
On mercredi 9 octobre 2019 18:28:40 CEST McLane, Kathleen A ERDC-RDE-GRL-VA
CIV wrote:
> Hello,
>
> I'm using gdaltransform to transform points from one datum to WGS84. In
> version 2.2.3 and 2.4.0 of GDAL, when I convert a point I receive a
> transformed latitude, longitude, and a new height value. In versions 2.4.1
> and 3.0.1, when I convert a point I receive a transformed latitude and
> longitude but height always equals 0. Attached are examples of the height
> value issue. Is this a GDAL error, or am I doing something wrong?

Your examples show more a difference at the PROJ level, but indeed there have
been changes in PROJ 6 where doing a transformation between geographic CRS
only cause 2D corrections to be applied, as this is what is recommended by
EPSG. If you want corrections on ellipsoidal heights as well, you have to
operate in the geocentric coordinate domain.

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