Datum Transformation Issues

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Datum Transformation Issues

Nick Fordes
Hi - 

I am using the Proj4js library and am having trouble successfully transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011) (EPSG:6317).

I have bee successful in entering coordinates into the following tool and generating results for going from WGS83 (EPSG4326) to NAD83 (2011) (EPSG:6317), however, there is no transformation applied. 


Is it possible to provide me with the transformation strings needed to accomplish this transformation?

Any guidance would be much appreciated. 

Nick Fordes

LocusView Solutions


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Re: Datum Transformation Issues

rgreenwood
On Wed, Feb 22, 2017 at 10:26 AM, Nick Fordes <[hidden email]> wrote:
Hi - 

I am using the Proj4js library and am having trouble successfully transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011) (EPSG:6317).

Are you getting an error or incorrect results? The espg definitions for 5332 and 6317 are the same (see below) but that's not to say they are correct.

# ITRF2008 <5332> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
# NAD83(2011) <6317> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
 
I have bee successful in entering coordinates into the following tool and generating results for going from WGS83 (EPSG4326) to NAD83 (2011) (EPSG:6317), however, there is no transformation applied. 

"NAD" datums are tied to the North American continental plate, "WGS" datums are tied to the center of the earth. To get meter or sub-meter accuracy transformations you need to use a grid shift transform. Is that what you're looking for when you say that no transformation is applied?




--
Richard W. Greenwood, PLS
www.greenwoodmap.com

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Re: Datum Transformation Issues

Nick Fordes
Yes - 

I am hoping to achieve a sub-meter transformation between the two datums.  Also - we would ideally like to go from ITRF 2008 to Is Proj4js an appropriate tool to do this?  Can it handle a grid shift transform?

Thanks,

Nick

On Wed, Feb 22, 2017 at 1:02 PM Richard Greenwood <[hidden email]> wrote:
On Wed, Feb 22, 2017 at 10:26 AM, Nick Fordes <[hidden email]> wrote:
Hi - 

I am using the Proj4js library and am having trouble successfully transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011) (EPSG:6317).

Are you getting an error or incorrect results? The espg definitions for 5332 and 6317 are the same (see below) but that's not to say they are correct.

# ITRF2008 <5332> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
# NAD83(2011) <6317> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
 
I have bee successful in entering coordinates into the following tool and generating results for going from WGS83 (EPSG4326) to NAD83 (2011) (EPSG:6317), however, there is no transformation applied. 

"NAD" datums are tied to the North American continental plate, "WGS" datums are tied to the center of the earth. To get meter or sub-meter accuracy transformations you need to use a grid shift transform. Is that what you're looking for when you say that no transformation is applied?




--
Richard W. Greenwood, PLS
www.greenwoodmap.com

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Re: Datum Transformation Issues

rgreenwood


On Wed, Feb 22, 2017 at 12:21 PM, Nick Fordes <[hidden email]> wrote:
Yes - 

I am hoping to achieve a sub-meter transformation between the two datums.  Also - we would ideally like to go from ITRF 2008 to Is Proj4js an appropriate tool to do this?  Can it handle a grid shift transform?

proj4js does not support grid shift transformations. Proj4 does but the epsg codes don't always reference the grid shift files. The Proj4 North American grid shift files that I'm aware of are tied to State Plane coordinate systems. I'm not aware of a grid shift file(s) covering the whole continent, which is what it looks like you're wanting?

Rich

 
Thanks,

Nick


On Wed, Feb 22, 2017 at 1:02 PM Richard Greenwood <[hidden email]> wrote:
On Wed, Feb 22, 2017 at 10:26 AM, Nick Fordes <[hidden email]> wrote:
Hi - 

I am using the Proj4js library and am having trouble successfully transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011) (EPSG:6317).

Are you getting an error or incorrect results? The espg definitions for 5332 and 6317 are the same (see below) but that's not to say they are correct.

# ITRF2008 <5332> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
# NAD83(2011) <6317> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
 
I have bee successful in entering coordinates into the following tool and generating results for going from WGS83 (EPSG4326) to NAD83 (2011) (EPSG:6317), however, there is no transformation applied. 

"NAD" datums are tied to the North American continental plate, "WGS" datums are tied to the center of the earth. To get meter or sub-meter accuracy transformations you need to use a grid shift transform. Is that what you're looking for when you say that no transformation is applied?




--
Richard W. Greenwood, PLS
www.greenwoodmap.com



--
Richard W. Greenwood, PLS
www.greenwoodmap.com

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Re: Datum Transformation Issues

Melita Kennedy-2
In reply to this post by Nick Fordes


On Wed, Feb 22, 2017 at 11:35 AM, <[hidden email]> wrote:


----------------------------------------------------------------------

Message: 1
Date: Wed, 22 Feb 2017 17:26:10 +0000
From: Nick Fordes <[hidden email]>
To: [hidden email]
Subject: [MetaCRS] Datum Transformation Issues
Message-ID:
        <[hidden email]>
Content-Type: text/plain; charset="utf-8"

Hi -

I am using the Proj4js library and am having trouble successfully
transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011)
(EPSG:6317).

I have bee successful in entering coordinates into the following tool and
generating results for going from WGS83 (EPSG4326) to NAD83 (2011)
(EPSG:6317), however, there is no transformation applied.

https://mygeodata.cloud/cs2cs/

Is it possible to provide me with the transformation strings needed to
accomplish this transformation?

Any guidance would be much appreciated.

Nick Fordes

LocusView Solutions

------------------------------

Message: 2
Date: Wed, 22 Feb 2017 12:02:48 -0700
From: Richard Greenwood <[hidden email]>
To: Nick Fordes <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Subject: Re: [MetaCRS] Datum Transformation Issues
Message-ID:
        <CAHBySPZpv=+FiaHgff=[hidden email]>
Content-Type: text/plain; charset="utf-8"

On Wed, Feb 22, 2017 at 10:26 AM, Nick Fordes <[hidden email]>
wrote:

> Hi -
>
> I am using the Proj4js library and am having trouble successfully
> transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011)
> (EPSG:6317).
>

Are you getting an error or incorrect results? The espg definitions for
5332 and 6317 are the same (see below) but that's not to say they are
correct.

# ITRF2008 <5332> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
# NAD83(2011) <6317> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>


> I have bee successful in entering coordinates into the following tool and
> generating results for going from WGS83 (EPSG4326) to NAD83 (2011)
> (EPSG:6317), however, there is no transformation applied.
>

"NAD" datums are tied to the North American continental plate, "WGS" datums
are tied to the center of the earth. To get meter or sub-meter accuracy
transformations you need to use a grid shift transform. Is that what you're
looking for when you say that no transformation is applied?




--
Richard W. Greenwood, PLS
www.greenwoodmap.com

------------------------------

Message: 3
Date: Wed, 22 Feb 2017 19:21:37 +0000
From: Nick Fordes <[hidden email]>
To: Richard Greenwood <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Subject: Re: [MetaCRS] Datum Transformation Issues
Message-ID:
        <[hidden email]>
Content-Type: text/plain; charset="utf-8"

Yes -

I am hoping to achieve a sub-meter transformation between the two datums.
Also - we would ideally like to go from ITRF 2008 to Is Proj4js an
appropriate tool to do this?  Can it handle a grid shift transform?

Thanks,

Nick

On Wed, Feb 22, 2017 at 1:02 PM Richard Greenwood <
[hidden email]> wrote:

> On Wed, Feb 22, 2017 at 10:26 AM, Nick Fordes <[hidden email]>
> wrote:
>
> Hi -
>
> I am using the Proj4js library and am having trouble successfully
> transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011)
> (EPSG:6317).
>
>
> Are you getting an error or incorrect results? The espg definitions for
> 5332 and 6317 are the same (see below) but that's not to say they are
> correct.
>
> # ITRF2008 <5332> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
> # NAD83(2011) <6317> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
>
>
> I have bee successful in entering coordinates into the following tool and
> generating results for going from WGS83 (EPSG4326) to NAD83 (2011)
> (EPSG:6317), however, there is no transformation applied.
>
>
> "NAD" datums are tied to the North American continental plate, "WGS"
> datums are tied to the center of the earth. To get meter or sub-meter
> accuracy transformations you need to use a grid shift transform. Is that
> what you're looking for when you say that no transformation is applied?
>
>
> --
> Richard W. Greenwood, PLS
> www.greenwoodmap.com
>
------------------------------

Message: 4
Date: Wed, 22 Feb 2017 12:35:12 -0700
From: Richard Greenwood <[hidden email]>
To: Nick Fordes <[hidden email]>
Cc: "[hidden email]" <[hidden email]>
Subject: Re: [MetaCRS] Datum Transformation Issues
Message-ID:
        <CAHBySPa-N6e5MYcsbSJ_huShE2OUn=[hidden email]>
Content-Type: text/plain; charset="utf-8"

On Wed, Feb 22, 2017 at 12:21 PM, Nick Fordes <[hidden email]>
wrote:

> Yes -
>
> I am hoping to achieve a sub-meter transformation between the two datums.
> Also - we would ideally like to go from ITRF 2008 to Is Proj4js an
> appropriate tool to do this?  Can it handle a grid shift transform?
>

proj4js does not support grid shift transformations. Proj4 does but the
epsg codes don't always reference the grid shift files. The Proj4 North
American grid shift files that I'm aware of are tied to State Plane
coordinate systems. I'm not aware of a grid shift file(s) covering the
whole continent, which is what it looks like you're wanting?

Rich


> Thanks,
>
> Nick
>
>
> On Wed, Feb 22, 2017 at 1:02 PM Richard Greenwood <
> [hidden email]> wrote:
>
>> On Wed, Feb 22, 2017 at 10:26 AM, Nick Fordes <[hidden email]>
>> wrote:
>>
>> Hi -
>>
>> I am using the Proj4js library and am having trouble successfully
>> transforming coordindates from ITRF 2008 (EPSG:5332) to NAD83 (2011)
>> (EPSG:6317).
>>
>>
>> Are you getting an error or incorrect results? The espg definitions for
>> 5332 and 6317 are the same (see below) but that's not to say they are
>> correct.
>>
>> # ITRF2008 <5332> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
>> # NAD83(2011) <6317> +proj=geocent +ellps=GRS80 +units=m +no_defs  <>
>>
>>
>> I have bee successful in entering coordinates into the following tool and
>> generating results for going from WGS83 (EPSG4326) to NAD83 (2011)
>> (EPSG:6317), however, there is no transformation applied.
>>
>>
>> "NAD" datums are tied to the North American continental plate, "WGS"
>> datums are tied to the center of the earth. To get meter or sub-meter
>> accuracy transformations you need to use a grid shift transform. Is that
>> what you're looking for when you say that no transformation is applied?
>>
>>
>>
>>
>> --
>> Richard W. Greenwood, PLS
>> www.greenwoodmap.com
>>

--
Richard W. Greenwood, PLS
www.greenwoodmap.com

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MetaCRS mailing list
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------------------------------

End of MetaCRS Digest, Vol 88, Issue 1
**************************************

Nick,

There are no available grid files to convert between ITRF2008 and NAD83 (2011). There is a time-enabled transformation available from the NGS on this page: https://www.ngs.noaa.gov/CORS/coords.shtml

The time parts would allow you to convert at a particular epoch, but proj4js (nor proj4 as far as I know) doesn't support the time-parameters.

You can use the base 7 parameters which would take care of the majority of the difference between the two frames. The website says IGS08 rather than ITRF2008, but you can treat them as equivalent.

IGS08 --> NAD 83 (2011)
[12 common points]
t0 = 1997.0
x(t0) = 0.99343 m;
y(t0) = -1.90331m;
z(t0) = -0.52655 m
x(t0) = 25.91467 mas;
y(t0) = 9.42645 mas;
z(t0) = 11.59935 mas
s(t0) = 1.71504 · 10-9 (unitless)

This would turn in to

+wgs84=-0.99343,1.90331,0.52655,0.0259,0.0943,0.116,-0.001715

Note: all signs changed to swap direction as from NAD83(2011) to IGS08/ITRF08/WGS84. Then changed the rotation signs to convert from coordinate frame method to position vector method. proj4 supports the latter version only.

Melita


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