[Qgis-developer] Unexpected change in ESPG codes from shapefiles (in stable and dev)

[Kari Salovaara]

Hi,

in Finland we have map datasets free of charge to download from The 
National Land Survey of Finland (NLS). See 
http://www.maanmittauslaitos.fi/en/opendata
 From Topographic Database You can download in ESRI shape format any 
Finnish map area. In each area You'll get a number of shapefiles related 
to category and each category has also a *.prj file.

The problem arises when You make a layer from any of these shapefiles in 
following example;
1. set project CRS to Finnish ESPG:3067 ( which is on the list EPSG:3067 
- ETRS89 / ETRS-TM35FIN)
2. make a layer from shapefile, as it has *.prj which starts like 
PROJCS["ETRF89_ETRS_TM35FIN",GEOGCS["GCS_ETRS89",DATUM["D_ETRS_1989"....
You expect the layer CRS to be 3067 but when You look to layer 
properties it shows 3047 (in the dialog list EPSG:3047 - ETRS89 / 
ETRS-TM35)
(which means, I think, 
PROJCS["ETRF89_ETRS_TM35",GEOGCS["GCS_ETRS89",DATUM["D_ETRS_1989")... 
small but nasty difference.

This problem can cause difficulties when creating scripts for automation 
etc.
And very odd is that when You have created an empty project with CRS set 
to 3067 and create a shapefile its *.prj file starts 
PROJCS["ETRS89_TM35FIN_E_N",GEOGCS["GCS_ETRS_1989",DATUM["D_ETRS_1989",
but in this case the EPSG is 3067.

For  my knowledge ETRS-TM35FIN is always and only EPSG:3067.

Could someone explain is this failure in QGIS or GDAL/OGR or PROJ.4?
This problem has been tested in 2.6.1 (latest update in OpenSuse12.3) 
and 2.7.0 (nightly) versions and both linux and win 7 environments.
Finnish QGIS society are waiting this Christmas Question answer with 
interest. ;)

With warm and kind regards,
Kari

PS. This has been discussed here locally without any final 
understanding. Some guess has been that program only looks and takes 
first some nearly suitable code and uses it.

-- 
Kari Salovaara
Hanko, Finland

"Volunteers do not necessarily have the time; they just have the heart."
  ~ Elizabeth Andrew