FIMPORT

Description

FIMPORT transfers the image and all auxiliary information from a source file to a newly created PCIDSK file. All GDB-supported file types can be imported.

Parameters

Name	Type	Caption	Length	Value range
FILI*	String	Input file name	1 - 192
FILO*	String	Output file name	1 - 192
DBIW	Integer	Raster input window	0 - 4	Xoffset, Yoffset, Xsize, Ysize
POPTION*	String	Pyramid options	3 - 32	OFF, NEAREST, AVERAGE, MODE Default: AVERAGE
DBLAYOUT	String	Data Layout	0 - 192	PIXEL \| BAND \| FILE \| TILED \| TILEDN \| TILED JPEG \| TILED QUADTREE \| TILED RLE

* Required parameter

Parameter descriptions

FILI

The name of the GDB-supported file to import to PCIDSK format.

FILO

The name of the PCIDSK output file to create.

DBIW

The raster window (Xoffset, Yoffset, Xsize, Ysize) that is read from the input layers. If no value is specifed for this parameter, the entire layer is processed by default.

Xoffset, Yoffset define the upper-left starting pixel coordinates of the window. Xsize is the number of pixels that define the window width. Ysize is the number of lines that define the window height.

POPTION

The resampling method to use to compute the overview levels.

Acceptable values include:

OFF: Does not compute overviews. Although this option delays the browsing of an image, processing is quick, and it uses a minimum amount of disk space.
NEAREST: Applies a closest-neighbor resample. This is the default value.
AVERAGE: Calculates the average value of all of the pixels that contribute to the overview pixel. Use this option with continuous-tone images. AVERAGE produces a better-looking and more interpretable overview than NEAREST; however, you cannot use this option with classified, pseudocolor, or thematic images because it introduces intermediate values not found in the original image.
MODE: Takes the mode of the pixels contributing to the overview pixel. This option is suitable for use with classified, pseudocolored, or thematic images, but not continuous-tone images.

To compute thematic image overviews, such as classification results, use MODE. With continuous-tone images, especially radar images, use AVERAGE. Building overviews by using AVERAGE or MODE can be significantly slower than with NEAREST. If you do not know the characteristics of an image, or if the speed is your primary consideration in preparing the image overviews, use the NEAREST option.

DBLAYOUT

The layout of the image data in the new PCIDSK file.

Supported values include:

PIXEL: Pixel interleaved
BAND: Band interleaved; this is the default value
FILE: File interleaved
TILED: Tiled with a default tile size
TILEDN: Tiled with n x n pixel tiles
TILED JPEG: Tiled with JPEG compression
TILED QUADTREE: Tiled with QUADTREE compression
TILEDN RLE: Tiled with RLE compression and n x n pixel tiles

The specified layout is based primarily on performance. Band interleaved stores the data together for one band and provides a better performance when bands are not all being accessed at all times. Pixel interleaved stores the data for all bands together at a particular pixel and may provide improved performance when all bands are used at once. File interleaved is similar to band interleaved, but the image-channel data is stored in external files (one file for each band).

Tiled files organize the image in several square sub-images; these may be much faster to access when only a sub-area is being extracted, as in file viewing. Tiling is also the only format that supports compression formats, with a default of no compression.

JPEG compression is a lossy compression and is typically suitable for continuous images, such as airphotos.

Quadtree compression is another lossy compression, and provides good compression when images contain large blocks of pixels with the same value.

Run Length Encoding (RLE) compression is lossless, but only provides good compression for images in which long sequences of pixels have the same value, which is typical in pseudocolored or thematic images.

Details

FIMPORT imports all of the data contained in a GDB-supported file format into a newly created PCIDSK file. Georeferencing, lookup tables (LUT), pseudocolor tables (PCT), and vector data are also imported, in addition to image data.

When you run FIMPORT, it analyzes the input file, detects the type, creates a PCIDSK file, and then copies the image and auxiliary data to it.

With FIMPORT, you can only import files in formats that are supported by the GDB library. For a complete list of GDB-supported file types and their codes, see About Generic Database file formats.

If a file you import contains image channels, FIMPORT creaets overviews to accelerate image viewing. By default, the function applies nearest-neighbor resampling; however, you can change this by specifying another value for the the POPTION parameter. If necessary, you can prevent FIMPORT from creating overviews by specifing "OFF". turning off overview creation saves disk space, and files are imported more quickly. If necessary, you can later run the PYRAMID algorithm to add overviews to an existing file.

The value you specify for the DBLAYOUT parameter determines the image organization of the PCIDSK file being created.

FIMPORT is similar to the LINK algorithm; however, unlike LINK, FIMPORT works with all GDB-supported files. FIMPORT creates a duplicate copy of the image data, which LINK does not.

FIMPORT creates detail lines indicating the imagery size, number of channels, and any auxiliary information copied over.

Example

You import a subwindow of a large radar image. The overview pyramid levels are built with block averaging rather than the default nearest-neighbor resampling to make the resulting overviews easier to interpret.

EASI> FILI = "$PCIHOME/demo/irvine.pix"
EASI> FILO = "band1.pix"
EASI> DBIW = 
EASI> POPTION = "AVERAGE"
EASI> DBLAYOUT =			! Defaults to "BAND"

EASI> RUN FIMPORT

Environments	PYTHON :: EASI
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