uDIG

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
  • Component/s: visualization using map layer and style
  • 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
    09/Jul/10 6:38 AM
  2. geotiffZoom2.PNG
    48 kB
    09/Jul/10 6:38 AM
  3. geotiffZoom3.PNG
    307 kB
    09/Jul/10 6:38 AM

Issue Links

depends upon

Bug - A problem which impairs or prevents the functions of the product. GEOT-3195 Problem GeoTiff Reported

  • Major - Major loss of function.
  • Closed - The issue is considered finished, the resolution is correct. Issues which are not closed can be reopened.

Activity

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Gaudissart Vincent added a comment -
Three screen capture with different levels of zoom.
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Gaudissart Vincent added a comment - Three screen capture with different levels of zoom.
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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?
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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?
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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.
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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. "
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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
Permalink
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: