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</o:shapelayout></xml><![endif]--><div class=WordSection1><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Hi Bo Victor,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Thanks for your reply to my enquiry. The two files referred to in the discussion are attached.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I hope that this helps you.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>I do not know how to make these generally available to the whole QGIS list, so I am sending them to you off list.<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>Best wishes,<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'>David<o:p></o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>David Addy<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>10 Northgate Avenue<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Bury St Edmunds<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Suffolk<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>IP32 6BB<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Telephone 01284 704247<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Mobile 07766 178 459<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>Are you interested in the local history of West Suffolk? If so, try my local history site at:-<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>http://www.stedmundsburychronicle.com/index.htm<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>And including new for 2014, a picture gallery of our area during the Great War, 1914-1919<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'>http://www.stedmundsburychronicle.com/galleryww1/galleryww1home.htm<o:p></o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p><p class=MsoNormal><span style='font-size:11.0pt;font-family:"Calibri","sans-serif";color:#1F497D'><o:p> </o:p></span></p><div style='border:none;border-top:solid #B5C4DF 1.0pt;padding:3.0pt 0cm 0cm 0cm'><p class=MsoNormal><b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span lang=EN-US style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> Bo Victor Thomsen [via OSGeo.org] [mailto:<a href="/user/SendEmail.jtp?type=node&node=5095677&i=0" target="_top" rel="nofollow" link="external">[hidden email]</a>] <br><b>Sent:</b> 28 December 2013 09:33<br><b>To:</b> David Addy<br><b>Subject:</b> Re: Problem correctly reading Mapinfo TIF and TAB files into QGIS<o:p></o:p></span></p></div><p class=MsoNormal><o:p> </o:p></p><p class=MsoNormal>Nick - <br><br>Could you make a couple of "problem" and "no problem" tiff/tab files <br>available ? <br><br>Regards <br>Bo Victor Thomsen <br>Aestas-GIS <br>Denamrk <br><br>Den 27-12-2013 19:31, David Addy skrev: <o:p></o:p></p><div><p class=MsoNormal><div class='shrinkable-quote'><br>> In this area of the UK, a number of local authorities use Mapinfo for their <br>> Archaeology and Record Office services. This often involves reading <br>> historical maps in order to compare with current conditions on the ground. <br>> All such maps are calibrated within Mapinfo, and are usually in the form of <br>> .TIF files accompanied by a .TAB file giving the georeferencing data. As <br>> these departments are constantly under budgetary pressure there are many <br>> applications where the use of QGIS could result in considerable cost <br>> savings. However, it is necessary that existing maps should be easily read <br>> by QGIS and correctly located, <br>> without a cumbersome file conversion process. <br>> An example of such maps is the 1880s First Series 1:2500 scale county <br>> Ordnance Survey maps for Suffolk. At this scale it takes a large number of <br>> tiles to cover a whole county. In a sample dozen of such maps around Bury St <br>> Edmunds, only four were correctly located by QGIS. My mapping friend Nick <br>> Hopton has kindly addressed this problem to the GDAL forum, using two sample <br>> tiles, one of which works in QGIS and the other does not. The discussion on <br>> this is reproduced below, and appears to come down to the size of the error <br>> found by GDAL in its attempted transformation. AS this error seems to be <br>> acceptable within Mapinfo, I do not quite understand why it cannot work <br>> equally well within QGIS. <br>> Obviously this must be a critical issue for all Mapinfo users who would like <br>> to adopt QGIS, but find that this problem causes their evaluations to fail <br>> at the first hurdle. Like myself, these users are not experts in the <br>> technical details of map projections, nor the problems of making pre-1936 <br>> maps fit within today's UK Ordnance Survey OSGB36 Grid References. <br>> However, we need to know whether anyone knows how to persuade QGIS/GDAL to <br>> locate these tiles in the correct place please? <br>> <br>> -------------------------------------------------- <br>> PROBLEM PREVIOUSLY ADDRESSED TO GDAL FORUM: <br>> <br>> A friend, a relative newcomer to GIS, is having problems loading some of the <br>> TIFs created with Mapinfo into QGIS. Each TIF has a TAB file and in some <br>> cases the TAB file is interpreted correctly and in other cases the TAB file <br>> is (apparently) not recognised. <br>> I think this might be a problem with Gdal rather than a problem with QGIS. <br>> Taking just two of the TIFs, the output from gdalinfo when run on <br>> 33044061.TIF indicates that things are working as they should. However, when <br>> gdalinfo is run on 33044071.TIF the spatial data in its TAB file is not <br>> recognised. See the listings below. <br>> <br>> The strange thing is that all of the TIFs can successfully be converted from <br>> TIF to GeoTIFF using gdalwarp. (But it is important to my friend that he <br>> should be able to open Mapinfo raster images directly.) <br>> <br>> Any ideas? <br>> <br>> Regards, <br>> Nick. <br>> <br>> <br>> Contents of 33044061.TAB: <br>> ------------------------ <br>> !table <br>> !version 300 <br>> !charset WindowsLatin1 <br>> <br>> Definition Table <br>> File "33044061.tif" <br>> Type "RASTER" <br>> (582429,263569) (1,7594) Label "Pt 1", <br>> (582372,265177) (1,0) Label "Pt 2", <br>> (584784,265263) (11335,1) Label "Pt 3", <br>> (584841,263655) (11335,7594) Label "Pt 4" <br>> CoordSys Earth Projection 8, 79, "m", -2, 49, 0.9996012717, 400000, <br>> -100000 <br>> Units "m" <br>> <br>> Results of running gdalinfo on 33044061.TIF: <br>> ------------------------------------------- <br>> nick@nick-6150M2MA:~/Desktop/tabstuff$ gdalinfo 33044061.TIF <br>> Warning 1: TIFFFetchNormalTag:ASCII value for tag "ImageDescription" <br>> contains null byte in value; value incorrectly truncated <br>> during reading due to implementation limitations <br>> Driver: GTiff/GeoTIFF <br>> Files: 33044061.TIF <br>> Size is 11335, 7594 <br>> Coordinate System is: <br>> PROJCS["unnamed", <br>> GEOGCS["unnamed", <br>> DATUM["OSGB_1936", <br>> SPHEROID["Airy 1930",6377563.396,299.3249646], <br>> TOWGS84[375,-111,431,-0,-0,-0,0]], <br>> PRIMEM["Greenwich",0], <br>> UNIT["degree",0.0174532925199433]], <br>> PROJECTION["Transverse_Mercator"], <br>> PARAMETER["latitude_of_origin",49], <br>> PARAMETER["central_meridian",-2], <br>> PARAMETER["scale_factor",0.9996012717], <br>> PARAMETER["false_easting",400000], <br>> PARAMETER["false_northing",-100000], <br>> UNIT["Meter",1]] <br>> GeoTransform = <br>> 582371.785312838, 0.2128106799708935, 0.007506419931892793 <br>> 265177.0453393974, 0.007597130759524194, -0.2117600570261751 <br>> Metadata: <br>> TIFFTAG_IMAGEDESCRIPTION= <br>> TIFFTAG_XRESOLUTION=300 <br>> TIFFTAG_YRESOLUTION=300 <br>> TIFFTAG_MINSAMPLEVALUE=0 <br>> TIFFTAG_MAXSAMPLEVALUE=1 <br>> TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch) <br>> Image Structure Metadata: <br>> COMPRESSION=CCITTFAX4 <br>> INTERLEAVE=BAND <br>> MINISWHITE=YES <br>> Corner Coordinates: <br>> Upper Left ( 582371.785, 265177.045) ( 0d40'19.83"E, 52d15'14.75"N) <br>> Lower Left ( 582428.789, 263568.939) ( 0d40'19.71"E, 52d14'22.68"N) <br>> Upper Right ( 584783.994, 265263.159) ( 0d42'27.09"E, 52d15'14.63"N) <br>> Lower Right ( 584840.998, 263655.053) ( 0d42'26.92"E, 52d14'22.57"N) <br>> Center ( 583606.392, 264416.049) ( 0d41'23.39"E, 52d14'48.66"N) <br>> Band 1 Block=512x512 Type=Byte, ColorInterp=Palette <br>> Image Structure Metadata: <br>> NBITS=1 <br>> Color Table (RGB with 2 entries) <br>> 0: 255,255,255,255 <br>> 1: 0,0,0,255 <br>> nick@nick-6150M2MA:~/Desktop/tabstuff$ <br>> <br>> Contents of 33044071.TAB: <br>> ------------------------ <br>> !table <br>> !version 300 <br>> !charset WindowsLatin1 <br>> <br>> Definition Table <br>> File "33044071.tif" <br>> Type "RASTER" <br>> (584841,263655) (1,7576) Label "Pt 1", <br>> (584784,265263) (1,0) Label "Pt 2", <br>> (587197,265349) (11335,1) Label "Pt 3", <br>> (587254,263740) (11335,7576) Label "Pt 4" <br>> CoordSys Earth Projection 8, 79, "m", -2, 49, 0.9996012717, 400000, <br>> -100000 <br>> Units "m" <br>> <br>> Results of running gdalinfo on 33044071.TIF: <br>> ------------------------------------------- <br>> nick@nick-6150M2MA:~/Desktop/tabstuff$ gdalinfo 33044071.TIF <br>> Warning 1: TIFFFetchNormalTag:ASCII value for tag "ImageDescription" <br>> contains null byte in value; value incorrectly truncated <br>> during reading due to implementation limitations <br>> Driver: GTiff/GeoTIFF <br>> Files: 33044071.TIF <br>> Size is 11335, 7576 <br>> Coordinate System is `' <br>> GCP Projection = <br>> PROJCS["unnamed", <br>> GEOGCS["unnamed", <br>> DATUM["OSGB_1936", <br>> SPHEROID["Airy 1930",6377563.396,299.3249646], <br>> TOWGS84[375,-111,431,-0,-0,-0,0]], <br>> PRIMEM["Greenwich",0], <br>> UNIT["degree",0.0174532925199433]], <br>> PROJECTION["Transverse_Mercator"], <br>> PARAMETER["latitude_of_origin",49], <br>> PARAMETER["central_meridian",-2], <br>> PARAMETER["scale_factor",0.9996012717], <br>> PARAMETER["false_easting",400000], <br>> PARAMETER["false_northing",-100000], <br>> UNIT["Meter",1]] <br>> GCP[ 0]: Id=Pt 1, Info= <br>> (1,7576) -> (584841,263655,0) <br>> GCP[ 1]: Id=Pt 2, Info= <br>> (1,0) -> (584784,265263,0) <br>> GCP[ 2]: Id=Pt 3, Info= <br>> (11335,1) -> (587197,265349,0) <br>> GCP[ 3]: Id=Pt 4, Info= <br>> (11335,7576) -> (587254,263740,0) <br>> Metadata: <br>> TIFFTAG_IMAGEDESCRIPTION= <br>> TIFFTAG_XRESOLUTION=300 <br>> TIFFTAG_YRESOLUTION=300 <br>> TIFFTAG_MINSAMPLEVALUE=0 <br>> TIFFTAG_MAXSAMPLEVALUE=1 <br>> TIFFTAG_RESOLUTIONUNIT=2 (pixels/inch) <br>> Image Structure Metadata: <br>> COMPRESSION=CCITTFAX4 <br>> INTERLEAVE=BAND <br>> MINISWHITE=YES <br>> Corner Coordinates: <br>> Upper Left ( 0.0, 0.0) <br>> Lower Left ( 0.0, 7576.0) <br>> Upper Right (11335.0, 0.0) <br>> Lower Right (11335.0, 7576.0) <br>> Center ( 5667.5, 3788.0) <br>> Band 1 Block=512x512 Type=Byte, ColorInterp=Palette <br>> Image Structure Metadata: <br>> NBITS=1 <br>> Color Table (RGB with 2 entries) <br>> 0: 255,255,255,255 <br>> 1: 0,0,0,255 <br>> ------------------------------------------------------------------- <br>> <br>> <br>> FRANK WARMERDAM REPLIED: <br>> <br>> <br>> Nick, <br>> <br>> I haven't tried the .TAB files locally, but I see they are both resulting in <br>> georeferencing info. The one is expressed as a <br>> <br>> geotransform with rotation and shear while the other is expressed as ground <br>> control points. <br>> <br>> I believe that the .TAB reader attempts to compute a geotransform from the <br>> points in the TAB and if it can do so with minimal <br>> <br>> error then that is what is returned - a solution easier to utilize in QGIS <br>> and other applications. <br>> <br>> If the control points do not represent a clean affine transformation for the <br>> image then it falls back to returning them as <br>> <br>> ground control points which relatively few applications can utilize <br>> directly. <br>> <br>> One "solution" is to run gdalwarp to transform the image that isn't <br>> currently working so well into a north up affine <br>> <br>> transformation style image. <br>> eg. <br>> <br>> gdalwarp 33044071.TIF 33044071_northup.TIF <br>> <br>> This warp will be done using the control points (ironically also using a <br>> best fit first order polynomial). <br>> <br>> The code responsible for the decision is this from gdal/gcore/gdal_misc.cpp: <br>> <br>> <br>> /* -------------------------------------------------------------------- */ <br>> <br>> /* Try to convert the GCPs into a geotransform definition, if */ <br>> <br>> /* possible. Otherwise we will need to use them as GCPs. */ <br>> <br>> /* -------------------------------------------------------------------- */ <br>> <br>> if( !GDALGCPsToGeoTransform( nCoordinateCount, asGCPs, padfGeoTransform, <br>> <br>> FALSE ) ) <br>> <br>> { <br>> <br>> if (pnGCPCount && ppasGCPs) <br>> <br>> { <br>> <br>> CPLDebug( "GDAL", <br>> <br>> "GDALLoadTabFile(%s) found file, wasn't able to derive a\n" <br>> <br>> "first order geotransform. Using points as GCPs.", <br>> <br>> pszFilename ); <br>> <br>> <br>> <br>> <br>> *ppasGCPs = (GDAL_GCP *) <br>> <br>> CPLCalloc( sizeof(GDAL_GCP),nCoordinateCount ); <br>> <br>> memcpy( *ppasGCPs, asGCPs, sizeof(GDAL_GCP) * nCoordinateCount <br>> ); <br>> <br>> *pnGCPCount = nCoordinateCount; <br>> <br>> } <br>> <br>> } <br>> <br>> else <br>> <br>> { <br>> <br>> GDALDeinitGCPs( nCoordinateCount, asGCPs ); <br>> <br>> } <br>> <br>> I suspect if you change the FALSE to TRUE in the arguments to <br>> GDALGCPsToGeoTransform() you wlil always get an affine <br>> <br>> transform even when it is not a very good fit. <br>> <br>> <br>> <br>> -- <br>> View this message in context: <a href="http://osgeo-org.1560.x6.nabble.com/Problem-correctly-reading-Mapinfo-TIF-and-TAB-files-into-QGIS-tp5095647.html" target="_top" rel="nofollow" link="external">http://osgeo-org.1560.x6.nabble.com/Problem-correctly-reading-Mapinfo-TIF-and-TAB-files-into-QGIS-tp5095647.html</a><br>> Sent from the Quantum GIS - User mailing list archive at Nabble.com. <br>> _______________________________________________ <br>> Qgis-user mailing list <br>> <a href="/user/SendEmail.jtp?type=node&node=5095673&i=0" target="_top" rel="nofollow" link="external">[hidden email]</a> <br>> <a href="http://lists.osgeo.org/mailman/listinfo/qgis-user" target="_top" rel="nofollow" link="external">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><o:p></o:p></p></div><p class=MsoNormal style='margin-bottom:12.0pt'></div>_______________________________________________ <br>Qgis-user mailing list <br><a href="/user/SendEmail.jtp?type=node&node=5095673&i=1" target="_top" rel="nofollow" link="external">[hidden email]</a> <br><a href="http://lists.osgeo.org/mailman/listinfo/qgis-user" target="_top" rel="nofollow" link="external">http://lists.osgeo.org/mailman/listinfo/qgis-user</a><br><br><o:p></o:p></p><div class=MsoNormal align=center style='text-align:center'><hr size=1 width="100%" noshade style='color:#CCCCCC' align=center></div><div><div><p class=MsoNormal><b><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#444444'>If you reply to this email, your message will be added to the discussion below:<o:p></o:p></span></b></p></div><p class=MsoNormal><span style='font-size:9.0pt;font-family:"Tahoma","sans-serif";color:#444444'><a href="http://osgeo-org.1560.x6.nabble.com/Problem-correctly-reading-Mapinfo-TIF-and-TAB-files-into-QGIS-tp5095647p5095673.html" target="_top" rel="nofollow" link="external">http://osgeo-org.1560.x6.nabble.com/Problem-correctly-reading-Mapinfo-TIF-and-TAB-files-into-QGIS-tp5095647p5095673.html</a> <o:p></o:p></span></p></div><div style='margin-top:4.8pt'><p class=MsoNormal style='line-height:18.0pt'><span style='font-size:8.5pt;font-family:"Tahoma","sans-serif";color:#666666'>To unsubscribe from Problem correctly reading Mapinfo TIF and TAB files into QGIS, <a href="" target="_top" rel="nofollow" link="external">click here</a>.<br><a href="http://osgeo-org.1560.x6.nabble.com/template/NamlServlet.jtp?macro=macro_viewer&id=instant_html%21nabble%3Aemail.naml&base=nabble.naml.namespaces.BasicNamespace-nabble.view.web.template.NabbleNamespace-nabble.view.web.template.NodeNamespace&breadcrumbs=notify_subscribers%21nabble%3Aemail.naml-instant_emails%21nabble%3Aemail.naml-send_instant_email%21nabble%3Aemail.naml" target="_top" rel="nofollow" link="external"><span style='font-size:7.0pt;font-family:"Times New Roman","serif"'>NAML</span></a> <o:p></o:p></span></p></div></div><div class="small"><br/><img src="/images/icon_attachment.gif" > <strong>33044061.TAB</strong> (422 bytes) <a href="http://osgeo-org.1560.x6.nabble.com/attachment/5095677/0/33044061.TAB" target="_top" rel="nofollow" link="external">Download Attachment</a><br/><img src="/images/icon_attachment.gif" > <strong>33044061.TIF</strong> (591K) <a href="http://osgeo-org.1560.x6.nabble.com/attachment/5095677/1/33044061.TIF" target="_top" rel="nofollow" link="external">Download Attachment</a><br/><img src="/images/icon_attachment.gif" > <strong>33044071.TAB</strong> (422 bytes) <a href="http://osgeo-org.1560.x6.nabble.com/attachment/5095677/2/33044071.TAB" target="_top" rel="nofollow" link="external">Download Attachment</a><br/><img src="/images/icon_attachment.gif" > <strong>33044071.TIF</strong> (1M) <a href="http://osgeo-org.1560.x6.nabble.com/attachment/5095677/3/33044071.TIF" target="_top" rel="nofollow" link="external">Download Attachment</a></div>
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