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

Eduardo Rojas Rodríguez eduardo.rojas at soltig.net
Sat Jan 20 22:01:13 EST 2018

Greetings to all

let me introduce myself, my name is Eduardo Rojas Rodríguez I am a
Geographer specialized in GIS, I live in Costa Rica and I work for SOLTIG
who are the official commercial support of QGIS in Costa Rica.

Personally I am a fan of all OSGeo projects and I am currently very
committed to QGIS, all OSGeo projects and free software, I am given the task
to better understand the project of PROJ4 and how it works.

For this reason I realized that there is a problem with the definition that
is currently in PROJ4 for CRS 
EPSG 5456 and EPSG 5457 (Lambert Ocotepeque 1935 / Costa Rica North and
Lambert Ocotepeque 1935 / Costa Rica South).

The current definitions are:

EPSG 5456 current definition in PROJ4: (incorrect)
+proj=lcc +lat_1=10.46666666666667 +lat_0=10.46666666666667
+lon_0=-84.33333333333333 +k_0=0.99995696 +x_0=500000 +y_0=271820.522
+ellps=clrk66 +towgs84=205,96,-98,0,0,0,0 +units=m +no_defs

EPSG 5457 current definition in PROJ4: (incorrect)
+proj=lcc +lat_1=9 +lat_0=9 +lon_0=-83.66666666666667 +k_0=0.99995696
+x_0=500000 +y_0=327987.436 +ellps=clrk66 +towgs84=205,96,-98,0,0,0,0
+units=m +no_defs

After investigating the correct definition of CRS 5456 and 5457 and its
definition in PROJ4
should be replaced by:

EPSG 5456: Ocotepeque 1935 / Costa Rica Norte (correct definition)
+proj=lcc +lat_0=10.46666666666667  +lat_1=9.933333333 +lat_2=11
+lon_0=-84.3333333333 +k_0=0.99995696 +x_0=500000 +y_0=271820.522
+ellps=clrk66 +towgs84=213.116,9.358,-74.946,1.140,-2.980,3.100,-5.22
+units=m +no_defs

EPSG: 5457: Ocotepeque 1935 / Costa Rica Sur (correct definition)
+proj=lcc +lat_0=9 +lat_1=8.4666666667+lat_2=9.533333333
+lon_0=-83.666666667 +k_0=0.99995696 +x_0=500000 +y_0=327987.436
+ellps=clrk66 +towgs84=213.116,9.358,-74.946,1.140,-2.980,3.100,-5.22
+units=m +no_defs

with these definitions, the transformations that depend on the PROJ4 library
should be correct.

If you can help me explaining how and where to generate the report to
request the change of the definition, I thank you.

Is it just generating the report at https://github.com/OSGeo/proj.4/issues?

Thank you very much for the help

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

Sent from: http://osgeo-org.1560.x6.nabble.com/PROJ-4-f3840930.html

More information about the Proj mailing list