Questions about difference of result depending on the version of Proj4js

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Questions about difference of result depending on the version of Proj4js

Clément Ronzon
Hi,

A long time ago I was using the following version of Proj4js:
$Id: Proj.js 2956 2007-07-09 12:17:52Z steven $
Which, was returning 61.541418560123766°N, 24.054804906259587°E when converting 3343570m, 6829498m from EPSG:2393 (see definition below) to WGS84.

Today I'm running my app with version 2.3.4-alpha and it returns a WGS84 a bit different for the same conversion:
61.5409642803359°N, 24.057490703013173°E

If someone could explain to me why we have such a difference (151 meters) and/or which one of those two results should I trust in, I would be very grateful.

BTW, Proj4js is a very amazing project/library and is so useful!

Here is the definition of EPSG:2393 I use for both calculations:
+title=KKJ Zone 3 +proj=tmerc +lat_0=0 +lon_0=27 +k=1 +x_0=3500000 +y_0=0 +ellps=intl +towgs84=-96.0617,-82.4278,-121.7435,4.80107,0.34543,-1.37646,1.4964 +units=m +no_defs

Thank you.
Sincerely,
Clément Ronzon
Retorno Elias Nandino #50
Los Encinos 2 etapa 2
83293 Hermosillo, Sonora, MEXICO
Tel. # : 6621 96 18 66
 

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Re: Questions about difference of result depending on the version of Proj4js

rgreenwood
Running cs2cs at the command line I get:
echo 3343570 6829498 | cs2cs -f '%2f' +init=epsg:2393 +to +init=epsg:4326
24.054805    61.541419 25.243873
So the new version looks to be in error. Maybe it's not applying the datum transformation?

Rich




On Tue, Feb 17, 2015 at 2:04 PM, Clément Ronzon <[hidden email]> wrote:
Hi,

A long time ago I was using the following version of Proj4js:
$Id: Proj.js 2956 2007-07-09 12:17:52Z steven $
Which, was returning 61.541418560123766°N, 24.054804906259587°E when converting 3343570m, 6829498m from EPSG:2393 (see definition below) to WGS84.

Today I'm running my app with version 2.3.4-alpha and it returns a WGS84 a bit different for the same conversion:
61.5409642803359°N, 24.057490703013173°E

If someone could explain to me why we have such a difference (151 meters) and/or which one of those two results should I trust in, I would be very grateful.

BTW, Proj4js is a very amazing project/library and is so useful!

Here is the definition of EPSG:2393 I use for both calculations:
+title=KKJ Zone 3 +proj=tmerc +lat_0=0 +lon_0=27 +k=1 +x_0=3500000 +y_0=0 +ellps=intl +towgs84=-96.0617,-82.4278,-121.7435,4.80107,0.34543,-1.37646,1.4964 +units=m +no_defs

Thank you.
Sincerely,
Clément Ronzon
Retorno Elias Nandino #50
Los Encinos 2 etapa 2
83293 Hermosillo, Sonora, MEXICO
Tel. # : 6621 96 18 66
 

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Richard W. Greenwood, PLS
www.greenwoodmap.com

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Re: Questions about difference of result depending on the version of Proj4js

Clément Ronzon
Hey Richard,

Thank you for your answer, should I raise a bug in Proj4js's Github?

Thanks.

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Re: Questions about difference of result depending on the version of Proj4js

rgreenwood
Yes.

On Thu, Feb 19, 2015 at 1:44 PM, Clément Ronzon <[hidden email]> wrote:
Hey Richard,

Thank you for your answer, should I raise a bug in Proj4js's Github?

Thanks.



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Richard W. Greenwood, PLS
www.greenwoodmap.com

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