id,summary,reporter,owner,description,type,status,priority,milestone,component,version,severity,resolution,keywords,cc 5809,Failure to geolocate MAPINFO .TIF files calibrated by .TAB files,davesgrandad,warmerdam,"Where historical maps are calibrated within Mapinfo, these are usually output in the form of .TIF files accompanied by a .TAB file giving the georeferencing data. An example of such maps is the 1880s First Series 1:2500 scale county Ordnance Survey maps for Suffolk. At this scale it takes a large number of tiles to cover a whole county. In a sample dozen of such maps around Bury St Edmunds, only four were correctly located by GDAL called from within QGIS. The rest disappear from view. Two sample tiles are attached, which are adjacent to each other. One will be correctly located, while the other will not. It seems that GDAL will not properly locate the tile if the control points do not represent a clean affine transformation for the image. It falls back to returning them as ground control points which QGIS cannot utilize directly. This is likely to be a problem for all local authorities using old historic maps who would like to convert to QGIS. Can GDAL be tweaked to transform such tiles where the error is only slight? ",defect,closed,normal,2.0.0,default,unspecified,normal,fixed,,