[Proj] Correction of definition of CRS EPSG 5456 and 5457

Eduardo Rojas Rodríguez eduardo.rojas at soltig.net
Sat Jan 27 19:30:33 EST 2018

special thanks for you Andre 
and thanks you all for all the information and learning that I had

It seems that these are the parameters that are found in the deprecated
7parms transformation I think EPSG 5473

and these their anchor points to get the 10 parameters 

Apparently this is the transformation that ESRI uses within Arcgis in which
they get an accuracy below 1 meter 

So for me it's a bit strange that this is deprecated and get "better"
accuracy ??? 

I also made the tests and with the EPSG 5470 transformation  and I get
similars results fron 2 to 8 meters
213.27 m 
7.72 m 
-74.65 m 

the EPSG 5470 is the current default transformation within the EPSG for
Lambert Costa Rica Norte, but when QGIS is used within the definition of
PROJ4 for 5456 the + toWGS84 points out the parameters: 205, 96, -98 which
are derived from the concatencation of the transformations 6888 to 1171.

I have to configure QGIS to allow me to choose which transformation to use,
however I do not think it works for the "Reproject layer" tool in
processing. And in the -toWGS84 remains the 205, 96, -98 parameters. why is
not the 5470 parameters chosen by default and and written in the prj and

Im looking forward the “transformation pipelines” it sounds like the
solution to these problems.

For all, I must say that thanks to your help I am in the process of making
contact and meet with the IGN (National Geographic Institute of Costa Rica)
to start the process of defining a better transformation to send it to the
EPSG data base and thus arrive at PROJ4 because not only QGIS uses PROJ4 but
also other free programs such as Postgis that are crucial for the
development of the country.

PS: I have read that it is possible to shorten a definition of 10 parameters
in 7 according to
I will try and see what results I get

Eduardo Rojas Rodríguez
Analista en SIG
Soluciones en Tecnologías
Tel: 506 2505-5453
eduardo.rojas at soltig.net

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