On 12/18/2014 06:35 PM, Kari Salovaara wrote:
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.
It seems the proj4 string for both CRS is the same in my local
installation. Is it the same for you ? In that case, they are exactly
equivalent for QGis. When QGis finds a dataset without a clear CRS code,
it will parse the proj4 string to find the coordinate system and stop at
the first corresponding one.
Regards,
Leyan
_______________________________________________
Qgis-developer mailing list
[email protected]
http://lists.osgeo.org/mailman/listinfo/qgis-developer
