gvSIG-Desktop 1.9 Alpha. Manual de usuario.

gvSIG supports RAW images but before these can be loaded, users will be prompted for the necessary parameters.

To open a RAW image, select the option "Add layer" from the View menu or the corresponding button from the view toolbar. Click on "Add" and select the .RAW image to open. Choose the "gvSIG Raster Driver" option from the "Files of type" pull-down menu.

Loading .raw images

When opening the selected file, the following dialog window prompts for the RAW image parameters:

Configuration dialog for image parameters

RAW images basically consist of a continuous string of numbers without a header or other information. Therefore, users will need to supply the information through this dialog. To open a .RAW image you need to have writing permissions to the directory where the image is located.

The following parameters should be provided:

• Width: Image width in pixels.
• Height: Image height in pixels.
• Number of bands: Total number of bands in the image.
• Header size: This parameter is optional and can be omitted if unknown.
• File size: This field is filled automatically when the file is selected.
• Data type: Data type of the image. You need to select one data type from the list.
• Byte order: The order of the bytes in the image (LSB, MSB)
• Band interleaving: the way that the data is stored in the image: by pixel, by band or by line.

After completing the dialog, a header file VRT is created from the supplied parameters. The header file is written in XML format and will be saved with a VRT extension in the same data directory. If some of the parameters are unknown, the layer cannot be displayed correctly. The next time when you are loading the same .RAW file, you do not need to re-enter the parameters if you choose the "gvSIG Raster Driver" and select the VRT file with the stored parameters. However, if you want to load the image with different parameters, you need to load the RAW file again and follow the same procedure, which will overwrite the VRT file with the new parameters.