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Mistakes by configuring a new Custom Coordinate System [RDN2008 (ETRF2000) Italy zone (N-E) EPSG:6875]


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Good evening at everyone.

SINFI (National Information System for Italian Infrastructures) requires that the data be delivered to the reference system EPSG:6875 [1]

The SRS EPSG:6875 is called "RDN2008 / Italy zone (N-E)", based on the "RDN 2008" Datum.

The "Rete Dinamica Nazionale 2008", is the evolution of "European Terrestrial Reference Frame 2000" (ETRF 2000) . The RDN2008-ETRF2000 system is the new official Italian reference system since 2011 (D.M. del 10/11/2011) [2]

[1] http://epsg.io/6875 

[2] http://geomappando.com/wp-content/uploads/2016/07/DM-ETRF2000-RDN.pdf 

 

I have configured as follows a custom "DATUM_DEF" and a custom "COORDINATE_SYSTEM_DEF" in my "MyCoordSysDefs.fme" file:

ELLIPSOID_DEF GRS_1980 \
   DESC_NM "GRS_1980" \
   E_RAD 6378137 \
   P_RAD 6356752.314140

DATUM_DEF RDN2008                                             \
   DESC_NM    "Rete_Dinamica_Nazionale_2008"  \
   SOURCE     "PROJ4"                                         \
   ELLIPSOID  GRS_1980 \
   USE 7PARAMETER 
   DELTA_X 0                           \
   DELTA_Y 0                             \
   DELTA_Z 0                             \
   BWSCALE 0                          \
   ROT_X 0                          \
   ROT_Y 0                            \
   ROT_Z 0
   
COORDINATE_SYSTEM_DEF RDN2008_Italy_zone_N_E    \
    DESC_NM "RDN2008 / Italy zone (N-E)"      \
    EL_NAME GRS_1980    \
    DT_NAME RDN2008 \
    GROUP EUROPE \
    PARM1 12    \
    PROJ TM    \
    MAX_LAT 47.10                           \        
    MAX_LNG 18.99                           \        
    MIN_LAT 34.76                           \        
    MIN_LNG 5.93                            \    
    QUAD 1    \
    SCL_RED 0.9985000000    \
    UNIT METER    \
    X_OFF 7000000  

The new coordinate system is corrently loaded from FME and the reprojection works great.

FME Create the ESRI WKT Definition as follow:

PROJCS["RDN2008_Italy_zone_N_E",GEOGCS["GCS_RDN2008",DATUM["D_RDN2008",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",12],PARAMETER["scale_factor",0.9985],PARAMETER["false_easting",7000000],PARAMETER["false_northing",0],UNIT["Meter",1]]

 

The ESRI WKT Definition created from QGIS is the follow:

PROJCS["RDN2008_Italy_zone_N_E",GEOGCS["GCS_RDN2008",DATUM["D_Rete_Dinamica_Nazionale_2008",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",12],PARAMETER["scale_factor",0.9985],PARAMETER["false_easting",7000000],PARAMETER["false_northing",0],UNIT["Meter",1]]

 

To allow QGIS to recognise the EPSG:6785 reference system, the two WKT strings must be identical

 

I expected that in the string was reported the parameter DESC_NM    "Rete_Dinamica_Nazionale_2008" but it is not so. the name is reported.

The name cannot be longer than 24 characters.

 

Any suggestions?

 

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Best answer by andreaatsafe 27 May 2019, 23:30

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Hi @pdorio,

The best thing here is to create an exception file for the naming association between the Esri and FME coordinate system.

To do this you create a file named MyExceptions.db file, add a line to name the new coordinate system: ESRI|<fme coordinate system name>| <Esri_WKT string>.

 

The MyExceptions.db file can then be saved in: %USER%\\Documents\\FME\\CoordinateSystemExceptions, or a shared folder (defined in Tools > FME Options > Default Paths > Shared FME Folders).

This article outlines how you can create the exception file.

I have attached a zip containing the exception file that you could use to create this association between the FME WKT and Esri WKT definition. It has a line for the EPSG code, as well as a line with the Esri WKT string. Exception_EPSG6875.zip

For future reference, if you need to create another custom coordinate system, you can create the files using our online tool here. If you include the Esri WKT definition, it will also create the exception file.

Userlevel 2
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Hi @andreaatsafe

 

Thank you very much, your solution have solved my problem when i configure the output coordinate system using the full name RDN2008_Italy_zone_N_E

 

But if i instead select EPSG:6875 , then the output PRJ is not corresponding with what i have declared in the MyExceptions.db file.

 

Do you have any suggestions?

Badge +10

Hi @andreaatsafe

 

Thank you very much, your solution have solved my problem when i configure the output coordinate system using the full name RDN2008_Italy_zone_N_E

 

But if i instead select EPSG:6875 , then the output PRJ is not corresponding with what i have declared in the MyExceptions.db file.

 

Do you have any suggestions?

Hi @pdorio,

What version of FME are you using?

I have not been able to replicate this issue.

Perhaps you can share a sample workspace?

-Andrea

Userlevel 2
Badge +4

Hi @andreaatsafe

 

Thank you very much, your solution have solved my problem when i configure the output coordinate system using the full name RDN2008_Italy_zone_N_E

 

But if i instead select EPSG:6875 , then the output PRJ is not corresponding with what i have declared in the MyExceptions.db file.

 

Do you have any suggestions?

Hi @andreaatsafe I am using FME 2016. In short time my company will migrate to 2019.

 

To reproduce the mistake:

1. Configure MyCoordSysDefs.fme

2. Configure MyExceptions.db

3. Launch test.fmw

 

You obtain 2 shapefile. If you open the both *.prj files you can see that only the "RDN2008_Italy_zone_N_E.prj" correspond to the exceptions declared in MyExceptions.db

6875.zip

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Hi Pietro,

first line in file from Andrea ("EPSG|RDN2008_Italy_zone_N_E|6875") means to describe in a same way RDN2008_Italy_zone_N_E and EPSG:6875. It works for me in my tests. Alternatively You can add theese lines at the end of file "MyExceptions.db":

ESRI|EPSG:6875|PROJCS["RDN2008_Italy_zone_N_E",GEOGCS["GCS_RDN2008",DATUM["D_Rete_Dinamica_Nazionale_2008",SPHEROID["GRS_1980",6378137,298.257222101]],PRIMEM["Greenwich",0],UNIT["Degree",0.017453292519943295]],PROJECTION["Transverse_Mercator"],PARAMETER["latitude_of_origin",0],PARAMETER["central_meridian",12],PARAMETER["scale_factor",0.9985],PARAMETER["false_easting",7000000],PARAMETER["false_northing",0],UNIT["Meter",1]]

 

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