[gdal-dev] OGRCreateCoordinateTransformation()
Javier Jimenez Shaw
j1 at jimenezshaw.com
Sat Mar 19 05:12:40 PDT 2022
Hi
Is there a "more modern" way to use a geoid file that is not included in
the default ones? (let's say, a non open one, like the German)
EXTENSION["PROJ4_GRIDS","HT2_0.gtx"] seems to be "proj4 style", right?
Even mentioned months ago that the tag GEOIDMODEL meaning was changed by
EPSG somehow (or it was not clear at the beginning, and they implemented in
a different way). But I do not know is that working in PROJ.
When a user has a non-free geoid file, and want to use it with PROJ, what
is the proper procedure without changing "proj.db"? (I would prefer
something in the CRS WKT more than transformation pipeline. But it is just
a wish)
BTW, I do not want to use TOWGS84 (that was part of the problem above).
Thanks
Javier.
.___ ._ ..._ .. . ._. .___ .. __ . _. . __.. ... .... ._ .__
Entre dos pensamientos racionales
hay infinitos pensamientos irracionales.
On Sat, 19 Mar 2022 at 00:17, Steve Riddell <sriddell at geocue.com> wrote:
> Thanks very much, Even. For reporting the problem, I “packaged up” a case
> with CRS’s with EPGS codes. For the actual problem I’m working, the target
> CRS is a custom projection –no EPSG.
>
>
>
> *From:* Even Rouault <even.rouault at spatialys.com>
> *Sent:* Friday, March 18, 2022 5:05 PM
> *To:* Steve Riddell <sriddell at geocue.com>; gdal-dev at lists.osgeo.org
> *Subject:* Re: OGRCreateCoordinateTransformation()
>
>
>
> Steve,
>
> Fix in PROJ queued in https://github.com/OSGeo/PROJ/pull/3123
>
> The complexity of dealing with legacy features TOWGS84[] and PROJ4_GRIDS
> is highly stressing PROJ pipeline computation engine.
>
> Using the plain EPSG codes EPSG:4955 -> EPSG:4617+5713 would be much
> preferable here
>
> Even
>
> Le 18/03/2022 à 21:14, Steve Riddell a écrit :
>
> Hi,
>
>
>
> I’m getting an error (below) using GDAL trying to set up a transformation
> between NAD83(CSRS) geodetic, w/ ellipsoidal heights, and NAD83(CSRS)
> geodetic, CGVD28 heights. Similar transformations work fine on some
> datums, but fail on others. Hope someone can offer some insight. Note
> the if I don't use the PROJ4_GRIDS extension, I don't get the error, but I
> don't get the geoid adjustment either.
>
>
>
> COMPD_CS["NAD83(CSRS) + Ellipsoid (Meters)",
>
> GEOGCS["NAD83(CSRS)",
>
> DATUM["NAD83_Canadian_Spatial_Reference_System",
>
> SPHEROID["GRS 1980",6378137,298.257222101,
>
> AUTHORITY["EPSG","7019"]],
>
> TOWGS84[0,0,0,0,0,0,0],
>
> AUTHORITY["EPSG","6140"]],
>
> PRIMEM["Greenwich",0,
>
> AUTHORITY["EPSG","8901"]],
>
> UNIT["degree",0.0174532925199433,
>
> AUTHORITY["EPSG","9122"]],
>
> AUTHORITY["EPSG","4617"]],
>
> VERT_CS["Ellipsoid (Meters)",
>
> VERT_DATUM["Ellipsoid",2002],
>
> UNIT["metre",1,
>
> AUTHORITY["EPSG","9001"]],
>
> AXIS["ellipsoidal height",UP]]]
>
>
>
> COMPD_CS["NAD83(CSRS) + CGVD28 height - HT2_0",
>
> GEOGCS["NAD83(CSRS)",
>
> DATUM["NAD83_Canadian_Spatial_Reference_System",
>
> SPHEROID["GRS 1980",6378137,298.257222101,
>
> AUTHORITY["EPSG","7019"]],
>
> TOWGS84[0,0,0,0,0,0,0],
>
> AUTHORITY["EPSG","6140"]],
>
> PRIMEM["Greenwich",0,
>
> AUTHORITY["EPSG","8901"]],
>
> UNIT["degree",0.0174532925199433,
>
> AUTHORITY["EPSG","9122"]],
>
> AUTHORITY["EPSG","4617"]],
>
> VERT_CS["CGVD28 height - HT2_0",
>
> VERT_DATUM["Canadian Geodetic Vertical Datum of 1928",2005,
>
> EXTENSION["PROJ4_GRIDS","HT2_0.gtx"],
>
> AUTHORITY["EPSG","5114"]],
>
> UNIT["metre",1,
>
> AUTHORITY["EPSG","9001"]],
>
> AXIS["Gravity-related height",UP],
>
> AUTHORITY["EPSG","5713"]]]
>
>
>
>
>
> ERROR 6: Cannot find coordinate operations from `EPSG:4955' to
> `COMPOUNDCRS["NAD83(CSRS) + CGVD28 height -
> HT2_0",BOUNDCRS[SOURCECRS[GEOGCRS["NAD83(CSRS)",DATUM["NAD83 Canadian
> Spatial Reference System",ELLIPSOID["GRS
> 1980",6378137,298.257222101,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["geodetic
> latitude
> (Lat)",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["geodetic
> longitude
> (Lon)",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4617]]],TARGETCRS[GEOGCRS["WGS
> 84",DATUM["World Geodetic System 1984",ELLIPSOID["WGS
> 84",6378137,298.257223563,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,2],AXIS["latitude",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["longitude",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],ID["EPSG",4326]]],ABRIDGEDTRANSFORMATION["Transformation
> from NAD83(CSRS) to WGS84",METHOD["Position Vector transformation (geog2D
> domain)",ID["EPSG",9606]],PARAMETER["X-axis
> translation",0,ID["EPSG",8605]],PARAMETER["Y-axis
> translation",0,ID["EPSG",8606]],PARAMETER["Z-axis
> translation",0,ID["EPSG",8607]],PARAMETER["X-axis
> rotation",0,ID["EPSG",8608]],PARAMETER["Y-axis
> rotation",0,ID["EPSG",8609]],PARAMETER["Z-axis
> rotation",0,ID["EPSG",8610]],PARAMETER["Scale
> difference",1,ID["EPSG",8611]]]],BOUNDCRS[SOURCECRS[VERTCRS["CGVD28 height
> - HT2_0",VDATUM["Canadian Geodetic Vertical Datum of
> 1928"],CS[vertical,1],AXIS["gravity-related
> height",up,LENGTHUNIT["metre",1]],ID["EPSG",5713]]],TARGETCRS[GEOGCRS["WGS
> 84",DATUM["World Geodetic System 1984",ELLIPSOID["WGS
> 84",6378137,298.257223563,LENGTHUNIT["metre",1]]],PRIMEM["Greenwich",0,ANGLEUNIT["degree",0.0174532925199433]],CS[ellipsoidal,3],AXIS["latitude",north,ORDER[1],ANGLEUNIT["degree",0.0174532925199433]],AXIS["longitude",east,ORDER[2],ANGLEUNIT["degree",0.0174532925199433]],AXIS["ellipsoidal
> height",up,ORDER[3],LENGTHUNIT["metre",1]],ID["EPSG",4979]]],ABRIDGEDTRANSFORMATION["CGVD28
> height - HT2_0 to WGS84 ellipsoidal height",METHOD["GravityRelatedHeight to
> Geographic3D"],PARAMETERFILE["Geoid (height correction) model
> file","HT2_0.gtx",ID["EPSG",8666]]]]]'
>
>
>
> Thanks in advance for any assistance!
>
> Best regards,
>
> Steve
>
>
>
>
>
> Steve Riddell
>
> Software Engineering
>
> *GeoCue Group, Inc.*
>
> 520 6th Street | Madison, AL 35756 USA
>
> *Phone:* 256.461.8289 | *Fax:* 256.461.8249
>
> *LIDAR/Drone Mapping Software & Services **– True View® 3D Imaging
> Sensors **– Image/LIDAR Data Management Solutions*
>
> www.geocue.com support.geocue.com
>
>
>
>
>
>
>
> --
>
> http://www.spatialys.com
>
> My software is free, but my time generally not.
>
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