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Posted to user@sis.apache.org by Daniel E Harter <da...@bahwancybertek.com> on 2021/12/03 22:02:01 UTC
NTv2 Canada file
Hi,
I downloaded NTV2_0.GSB grid file from the Canadian Government site[1]. It is used in the transformations EPSG:1313 NAD27 to NAD83 (4) and EPSG:1693 NAD27 to WGS 84 (33). When I try to use either transform, I get the following in the console:
Dec 03, 2021 1:38:43 PM org.apache.sis.internal.referencing.provider.NTv2 createMathTransform
WARNING: Loading of "NTv2_0.gsb" done, but some records were ignored because of unrecognized keywords: DATUM_F, DATUM_T
NAD27 input: (51.325795, -115.15383774, NaN)
Transform EPSG:1313 NAD83 result: (51.325853158412635, -115.15382696154606, NaN)
Transform EPSG:1693 WGS84 result: (51.325853158412635, -115.15382696154606, NaN)
Expected result From Canada NTv2 webapp: (51.325841, -115.15486299, NaN)
The expected result is from https://webapp.geod.nrcan.gc.ca/geod/tools-outils/ntv2.php?locale=en. Is there anything that can be done or do I just have to avoid these transforms?
[1]: https://webapp.geod.nrcan.gc.ca/geod/data-donnees/transformations.php
Thanks,
Daniel
Re: NTv2 Canada file
Posted by Martin Desruisseaux <ma...@geomatys.com>.
Le 04/12/2021 à 18:58, Daniel E Harter a écrit :
> The problem turned out to be that I was using version 1.0 instead of
> 1.1. Once I updated my pom the warning message went away, and I got
> the correct result.
>
Thanks for the report. Maybe one problem of SIS project is that the
"release notes" for each release is a little bit light; the amount of
bug fixes at each release is much larger that what is reported in the
JIRA issue tracker.
Martin
RE: NTv2 Canada file
Posted by Daniel E Harter <da...@bahwancybertek.com>.
Hi Martin,
The problem turned out to be that I was using version 1.0 instead of 1.1. Once I updated my pom the warning message went away, and I got the correct result.
Thank you.
Daniel
From: Martin Desruisseaux <ma...@geomatys.com>
Sent: Friday, December 3, 2021 4:59 PM
To: user@sis.apache.org
Subject: Re: NTv2 Canada file
CAUTION: This email originated outside of BCT. Do not click links or open attachments unless you recognize the sender and know the content is safe.
Hello Daniel
I just downloaded the NTV2_0.gsb file from the webapp.geod.nrcan.gc.ca web site and tried to transform the "NAD27 input" point. I got the following result, which seem to match the expected result. No warning was reported during my test.
Expected: 51.325841, -115.15486299
Actual: 51.32584099858066 -115.1548629958289
Maybe the NTV2 file has been altered during the transfer? What is the output of "md5sum NTV2_0.gsb" on your file? In my case I get the following:
f91da910eb02304456c2f7372a596ead NTV2_0.gsb
Also which version of SIS is used, and is the system a Windows, Linus or MacOS system?
Martin
Le 03/12/2021 à 23:02, Daniel E Harter a écrit :
I downloaded NTV2_0.GSB grid file from the Canadian Government site[1]. It is used in the transformations EPSG:1313 NAD27 to NAD83 (4) and EPSG:1693 NAD27 to WGS 84 (33). When I try to use either transform, I get the following in the console:
Dec 03, 2021 1:38:43 PM org.apache.sis.internal.referencing.provider.NTv2 createMathTransform
WARNING: Loading of “NTv2_0.gsb” done, but some records were ignored because of unrecognized keywords: DATUM_F, DATUM_T
NAD27 input: (51.325795, -115.15383774, NaN)
Transform EPSG:1313 NAD83 result: (51.325853158412635, -115.15382696154606, NaN)
Transform EPSG:1693 WGS84 result: (51.325853158412635, -115.15382696154606, NaN)
Expected result From Canada NTv2 webapp: (51.325841, -115.15486299, NaN)
Re: NTv2 Canada file
Posted by Martin Desruisseaux <ma...@geomatys.com>.
Hello Daniel
I just downloaded the NTV2_0.gsb file from the webapp.geod.nrcan.gc.ca
web site and tried to transform the "NAD27 input" point. I got the
following result, which seem to match the expected result. No warning
was reported during my test.
Expected: 51.325841, -115.15486299
Actual: 51.32584099858066 -115.1548629958289
Maybe the NTV2 file has been altered during the transfer? What is the
output of "md5sum NTV2_0.gsb" on your file? In my case I get the following:
f91da910eb02304456c2f7372a596ead NTV2_0.gsb
Also which version of SIS is used, and is the system a Windows, Linus or
MacOS system?
Martin
Le 03/12/2021 à 23:02, Daniel E Harter a écrit :
> I downloaded NTV2_0.GSB grid file from the Canadian Government
> site[1]. It is used in the transformations EPSG:1313 NAD27 to NAD83
> (4) and EPSG:1693 NAD27 to WGS 84 (33). When I try to use either
> transform, I get the following in the console:
>
> Dec 03, 2021 1:38:43 PM
> org.apache.sis.internal.referencing.provider.NTv2 createMathTransform
>
> WARNING: Loading of “NTv2_0.gsb” done, but some records were ignored
> because of unrecognized keywords: DATUM_F, DATUM_T
>
> NAD27 input: (51.325795, -115.15383774, NaN)
>
> Transform EPSG:1313 NAD83 result: (51.325853158412635,
> -115.15382696154606, NaN)
>
> Transform EPSG:1693 WGS84 result: (51.325853158412635,
> -115.15382696154606, NaN)
>
> Expected result From Canada NTv2 webapp: (51.325841, -115.15486299, NaN)
>