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<TITLE>Re: [Qgis-user] Recognition of SRS in MapInfo-Files</TITLE>
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<P DIR=LTR><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial">Dear Community,</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">thanks for your replies. I was very busy this week, so I could make further tests not until today. Unfortunately after my tests today I’m more confused than before. But I will try to explain…</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">First I figured out that Bo Victor is right in my case too. After I opened a TAB-File with EPSG:25832 the layer SRS definition is exactly as he posted. So this problem will address gdal/ogr library.</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">Then I tried out ogrinfo for a TAB file with EPSG 31467 as Jürgen mentioned. The output shows TOWGS84 parameters! These are used within the automatically user defined layer SRS definition in QGIS as well, after I open a MapInfo TAB file with 31467. It seems that ogr always assumes that TOWGS84 parameters have to be used for EPSG 31467. Even though the CoordSys-String in MapInfo MIF file (CoordSys Earth Projection 8, 104, "m", 9, 0, 1, 3500000, 0) does not point at such parameters and I changed the build in SRS definition in QGIS. In my opinion this is not the best way, because it seems to be impossible to get the modified build in SRS for EPSG 31467 matched. The purpose for the modification was to make use of grid shift transformation with BETA2007 / NTv2 instead of using parameter transformation</FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial"> in general.</FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">In former times I had trouble with ogr and MapInfo too. But these problems were more easy to solve. Using ogr2org to get PostGIS tables to MapInfo TAB files with -s_srs EPSG 31467 parameter caused trouble. The same happens with EPSG:25832. In both cases MapInfo Tab files didn’t get the right projection in MapInfo. The reason are different DATUM parameters. To get around these problems I used ogrinfo for MapInfo TAB with EPSG 31467 and 25832 to save suitable SRS definition in text files first. After that I used ogr2org with –</FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial">a</FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial">_srs 31467.txt or –</FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial">a</FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial">_srs 25832.txt and everything went fine. </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">But in case of my recent problem I don’t have a chance to do the same, because everything happens automatically. Even though if the next QGIS-version will make use of the latest GDAL-library, the problem of detecting the proper build in SRS I my case isn’t solved. Maybe this will be difficult because MapInfo and ogr do not use equal IDs for projections ;-(</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">My workaround is to assign the proper SRS after opening a MapInfo TAB file. But users have to do this every time a MapInfo file is opened in QGIS. Some do not like this, some don’t understand this and some do both. </FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">I would be glad, if you have new ideas!</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">Best regards</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">Andreas</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">Ogrinfo output for MapInfo TAB file with EPSG:31467:</FONT></SPAN></P>
<UL DIR=LTR>
<P DIR=LTR><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial">Layer SRS WKT:</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">PROJCS["unnamed",</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> </FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"> <FONT FACE="Arial">GEOGCS["unnamed",</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de"><FONT FACE="Arial"> DATUM["DHDN_Potsdam_Rauenberg",</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de"><FONT FACE="Arial"> </FONT></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"> <FONT FACE="Arial">SPHEROID["Bessel 1841",6377397.155,299.1528128],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> TOWGS84[582,105,414,1.04,0.35,-3.08,8.3]],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> PRIMEM["Greenwich",0],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> UNIT["degree",0.0174532925199433]],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> PROJECTION["Transverse_Mercator"],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> PARAMETER["latitude_of_origin",0],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> PARAMETER["central_meridian",9],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> PARAMETER["scale_factor",1],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> PARAMETER["false_easting",3500000],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> PARAMETER["false_northing",0],</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial"> UNIT["Meter",1.0]]</FONT></SPAN></P>
</UL>
<P DIR=LTR><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><FONT FACE="Arial">User defined layer SRS definition for the same MapInfo TAB file opened in QGIS:</FONT></SPAN></P>
<UL DIR=LTR>
<P DIR=LTR><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="en-us"><FONT FACE="Arial">+proj=tmerc +lat_0=0 +lon_0=9 +k=1 +x_0=3500000 +y_0=0 +ellps=bessel +towgs84=582,105,414,1.04,0.35,-3.08,8.3 +units=m +no_defs</FONT></SPAN></P>
</UL>
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<P DIR=LTR><SPAN LANG="de"><I></I></SPAN><SPAN LANG="de"><I></I></SPAN><I><SPAN LANG="en-us"></SPAN></I></P>
<P DIR=LTR><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de-de"><FONT FACE="Arial">Im Auftrag</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de-de"><FONT FACE="Arial">Andreas Fischer</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de-de"><FONT FACE="Arial">Sachgebietsleiter</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de-de"><FONT FACE="Arial">Kreis Unna - Der Landrat</FONT></SPAN></P>
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<P DIR=LTR><SPAN LANG="de-de"><FONT FACE="Arial">Friedrich-Ebert-Straße 17</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de"></SPAN><SPAN LANG="de"></SPAN><SPAN LANG="de-de"><FONT FACE="Arial">59425 Unna</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de-de"><FONT FACE="Arial">Fon 02 3 03 27-44 16</FONT></SPAN></P>
<P DIR=LTR><SPAN LANG="de-de"><FONT FACE="Arial">Fax 0 23 03 27-28 96</FONT></SPAN></P>
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