uDIG
  1. uDIG
  2. UDIG-1694

Can not display correctly some Geotiff

    Details

    • Type: Bug Bug
    • Status: Open Open
    • Priority: Major Major
    • Resolution: Unresolved
    • Affects Version/s: UDIG 1.2.M9, UDIG 1.2.RC2, UDIG 1.2.RC3
    • Fix Version/s: None
    • Labels:
      None
    • Environment:
      XP

      Description

      The display of some geotiff is buggy.
      When you "zoom to layer", uDig displays a black square. Depending on the level of zoom, vertical white lines appear. The image only appears when a sufficient level of zoom is reached.

      The problem does not seem to come from the GeoTIFF file, because it opens properly under GlobalMapper, QGis, and even under the Windows viewer. Moreover, we have lots of file with these symptoms.

      In attachment, a geotiff with the problem.

      1. geotiffZoom1.PNG
        50 kB
      2. geotiffZoom2.PNG
        48 kB
      3. geotiffZoom3.PNG
        307 kB

        Issue Links

          Activity

          Hide
          Gaudissart Vincent added a comment -
          Three screen capture with different levels of zoom.
          Show
          Gaudissart Vincent added a comment - Three screen capture with different levels of zoom.
          Hide
          Andrea Antonello added a comment -
          Hi, I tried to load the tiff and I have a couple of comments:
          - the prj file is missing and I do not think there is a CRS contained in the image?
          - I loaded the tiff into gimp and there are 2 layers, one with the map and the other also gimp couldn't load. How was the tiff produced?

          Show
          Andrea Antonello added a comment - Hi, I tried to load the tiff and I have a couple of comments: - the prj file is missing and I do not think there is a CRS contained in the image? - I loaded the tiff into gimp and there are 2 layers, one with the map and the other also gimp couldn't load. How was the tiff produced?
          Hide
          Andrea Antonello added a comment -
          Ok, I just saw the images and that the WGS84 is the CRS, so ignore that. How was the tiff created?
          Show
          Andrea Antonello added a comment - Ok, I just saw the images and that the WGS84 is the CRS, so ignore that. How was the tiff created?
          Hide
          Gaudissart Vincent added a comment -
          That is what I know:

          The geotiff consists of two images:
          - A "scanned map" GeoTIFF, which is color-coded with 256 colors (or less) on 1 band.
          - A "transparency mask," always present in the file. It identifies the padded pixels wich have the color code "0" in the main picture.

          The TIFF tag "SampleFormat" is set to "1" (default) to specify an encoding on an unsigned integer value.

          I do not know the library used to generate this file. It is likely a library derived from GDAL.

          I hope this information will help you.
          Show
          Gaudissart Vincent added a comment - That is what I know: The geotiff consists of two images: - A "scanned map" GeoTIFF, which is color-coded with 256 colors (or less) on 1 band. - A "transparency mask," always present in the file. It identifies the padded pixels wich have the color code "0" in the main picture. The TIFF tag "SampleFormat" is set to "1" (default) to specify an encoding on an unsigned integer value. I do not know the library used to generate this file. It is likely a library derived from GDAL. I hope this information will help you.
          Hide
          Gaudissart Vincent added a comment -
          Here are some additional information on the specification related to these GeoTIFF.

          "
          The 'data' part of a ortho-image product type is composed of a single file GeoTIFF. This file may contain two sub-files (as defined in the "subfile" TIFF specification) and thus two IFD :
          one for the image itself and one for the possible transparency mask. The image itself is always described by the first IFD of the file.
          The transparency mask is used to encode the notion of padding, in the usual raster-spatial data.

          The transparency mask is a dual level image which can be superimposed with the picture described by the first IFD. The pixel value "1" means that the corresponding pixel in the main image is significant (it is part of the active area). Conversely, the pixel value "0" means that the corresponding pixel in the image have an unknown value (it is a padding pixel) and typically must be made transparent to the display.
          A transparency mask contains no GeoTIFF tag. As part of this specification, it was decided to use a mask with the same resolution and size as the main image. The transparency mask is thus directly superimposed (pixel by pixel) in the master image.
          "
          Show
          Gaudissart Vincent added a comment - Here are some additional information on the specification related to these GeoTIFF. " The 'data' part of a ortho-image product type is composed of a single file GeoTIFF. This file may contain two sub-files (as defined in the "subfile" TIFF specification) and thus two IFD : one for the image itself and one for the possible transparency mask. The image itself is always described by the first IFD of the file. The transparency mask is used to encode the notion of padding, in the usual raster-spatial data. The transparency mask is a dual level image which can be superimposed with the picture described by the first IFD. The pixel value "1" means that the corresponding pixel in the main image is significant (it is part of the active area). Conversely, the pixel value "0" means that the corresponding pixel in the image have an unknown value (it is a padding pixel) and typically must be made transparent to the display. A transparency mask contains no GeoTIFF tag. As part of this specification, it was decided to use a mask with the same resolution and size as the main image. The transparency mask is thus directly superimposed (pixel by pixel) in the master image. "
          Hide
          Jody Garnett added a comment -
          I have created a bug report against the GeoTools library providing our GeoTiff support. GEOT-3195. This issue has been linked and I have added you as a watcher so you can be informed of progress.
          Show
          Jody Garnett added a comment - I have created a bug report against the GeoTools library providing our GeoTiff support. GEOT-3195 . This issue has been linked and I have added you as a watcher so you can be informed of progress.
          Hide
          Jody Garnett added a comment -
          Looks like the bug is now closed; with the resolution won't fix. Apparently something is wrong with the source image?
          Show
          Jody Garnett added a comment - Looks like the bug is now closed; with the resolution won't fix. Apparently something is wrong with the source image?

            People

            • Assignee:
              Unassigned
              Reporter:
              Gaudissart Vincent
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              Dates

              • Created:
                Updated: