Surfer imports images in the Amira Stacked Slices format. One or more images are imported from separate files as specified by a description file. The description file can be created by the user or by another application. The recommended (though not mandatory) file name extension is .ASI.
The description file is an ordinary text file. Any lines in the file that begin with a pound (#) character are assumed to be comments and are ignored. Any other lines must adhere to the format described below.
Typically the file begins with a comment line that reads
# Amira Stacked Slices
Next comes the optional "pathname" line. If present, this line specifies the pathname of the directory where the image files are located. If the pathname line is not present, the software assumes the image files are located in the same directory as the description file.
Next comes the optional "pixelsize" line. If present, this line specifies the spacing of the lattice nodes for each pixel in application units.
pixelsize 0.1. 0.1
If the pixelsize line is not present, the default size is one unit per pixel.
Next comes the image list consisting of one or more lines, each of which specifies the file name of an image file to load. Each of these lines can also optionally specify an application Z position for each image slice.
The above example loads four image slices positioned at 10, 11, 12, and 15 units along the Z axis.
If the z positions are not given with the image file names, the default z positioning, which uses the larger of the x pixel size and y pixel size as the amount to space between each slice on the z axis, is used.
If the z positions are uniformly spaced, the imported lattice is of the "uniform" lattice type.
Finally, the file ends with a line containing the word "end."
Example 4: Description File
# Amira Stacked Slices
# Directory where image files live
# Pixel Size
pixelsize 0.5 0.5
# Image List
# Mark the end of the description file
The image files to which the description file refers may include any of the image file formats supported by the other filters, such as .JPG, .BMP, .PNG, .TGA, and so on.
Loading .ASI Files
Amira Stacked Slices .ASI files can be loaded to create a grid based map (i.e. Home | New Map | Contour) with the Open Grid dialog, or when using the functions in the Grid menu.
Import Options Dialog
No import options dialog is displayed.
Import Automation Options
No import options are available.
Note that the images referenced by any particular description file must all be of the same width and height (in pixels) and have the same color depth (in bits per pixel). If any referenced image differs in dimensions or color depth from the others, an error message displays and the import does not complete.