ArcGIS™ ECW JPEG 2000 Plug-in - Help Documentation

6. Known Problems and Limitations

1) When adding a plug-in supported image I receive a warning “Unknown Spatial Reference” and some images fail to display in their correct coordinates.

The georeferencing information is not recognized by the plug-in or ArcGIS^™ and appears as “<Undefined>”. Your image could be in a custom spatial reference that may be uncommon. For JPEG 2000 images, it could mean that your image does not have a valid EPSG code (to learn more about EPSG codes, visit http://www.epsg.org). The best workaround is to set the closest possible spatial reference information using ArcCatalog^™. The steps below describe the workaround:

1. Find and delete the corresponding .aux file for the image e.g. image.aux for image.ecw

2. Bring up the Raster Dataset Properties window in ArcCatalog^™ by right clicking on the image file and selecting Properties…

3. Select the Spatial Reference heading and then click on Edit

4. Click on Select… and choose the appropriate pre-defined coordinate system that matches the file’s original projection/datum.

5. Close ArcCatalog^™, start ArcMap^™ and then load the image file

6. Bring up the layer properties by right clicking on the image file, and select the source tab

7. Scroll down to the Data Source section and you will see the projection/datum information preserved

ArcGIS^™ 9.1 users please note: Unlike previous versions of ArcGIS^™, version 9.1 will completely disregard any spatial reference information in a dataset as soon as it does not recognize the datum and/or projection (common example is WGS84/Local). This results in images appearing in incorrect coordinates. To rectify this problem, you should download and install ArcGIS 9.1 Service Pack 2.

2) When viewing remote ECW and JPEG 2000 images over a slow network connection, distortion/discoloration appears in the top left corner of the image

This can be fixed by clicking the Refresh button on the plug-in’s toolbar. Setting the Wait for All View Data plug-in option should also help.

3) The progress status remains after the image is loaded

Change the view, use the Refresh button or go back to previous extents. If the window still remains, try selecting the blank window tab in the Windows task bar and use the Windows Alt+F4 keyboard shortcut to close the window. The progress status can be turned off in the plug-in options.

4) When zooming close into large raster datasets, the image appears black

This is a known problem with ArcGIS^™ 8.3. Download and install the following patch by ERSI “ArcGIS Desktop 8.3 RPF and Memory Management for Large Raster Data Patch” to fix the problem.

5) When viewing large ECW or JPEG 2000 images in ArcMap^™, there may be a long pause between roam and zooms or getting properties

This is the result of ArcMap^™ attempting to calculate statistics, and a status message appears at the lower left corner of the window. Hold the Esc key down to cancel the statistics calculation and continue.

6) When attempting to view ERS files, you receive message boxes indicating that the plug-in could not determine the band number

Close ArcGIS^™, delete the AUX files that are associated with the ERS files and try again.

7) ECW and JPEG 2000 images display at poor resolution and appear pixilated and blocky

ER Mapper has an option to turn smoothing on, thereby removing the pixilated appearance of an image. A similar feature is available in ArcMap^™. Refer to 5.2. Raster Options in ArcMap^™.

8) GDA94 / LCC South Australia (EPSG:3107) coordinate system limitation

For ArcGIS 9.1 users the EPSG code of this coordinate system has been changed to EPSG:102172, as this is the code supported by ArcGIS 9.1. Using EPSG:3107 will not work in ArcGIS 9.1.

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