[mapguide-trac] #268: TIFF Not Rendering When Bottom of Image Crosses Current Window

Tue Oct 2 04:56:10 EDT 2007

#268: TIFF Not Rendering When Bottom of Image Crosses Current Window
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 Reporter:  crispinatime  |         Owner:       
     Type:  defect        |        Status:  new  
 Priority:  medium        |     Milestone:  2.0  
Component:  General       |       Version:  1.2.0
 Severity:  major         |    Resolution:       
 Keywords:                |   External_id:       
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Comment (by crispinatime):

 Hi,

 Thanks for your time - it looks (from CPL_DEBUG-ON) that there is an issue
 with the final line of the image - so whenever the bottom of the image
 crosses the window there is a failure.  I have used this image in previous
 MG6.5 releases and (from memory) it comes direct from the supplier - in
 this case Ordnance Survey.

 On a connected note, why when my TFW says the image origin is at X,Y does
 MG/GDAL then use this as the centr of the upper-left pixel and offset the
 upper-left by half-a-unit.  Is this expected behaviour?  Is this
 consistent with my underatanding of how the image is processed in other
 systems reading the georef files?

  Regards,
   Crispin

 ERROR 1: IReadBlock failed at X offset 16, Y offset 78
 ERROR 1: D:\Data\EAC\StreetMappig_TINY/NS40NE.tif:PackBitsDecode: Not
 enough dat
 a for scanline 2048
 ERROR 1: TIFFReadEncodedTile() failed.

 ERROR 1: IReadBlock failed at X offset 16, Y offset 78
 GDAL: GDALClose(D:\Data\EAC\StreetMappig_TINY/NS40NE.tif)

 GDAL: 26501 block reads on 6241 block band 1 of
 D:\Data\EAC\StreetMappig_TINY/NS
 40NE.tif.

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Ticket URL: <http://trac.osgeo.org/mapguide/ticket/268#comment:2>
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