Note: Use the PCIMOD program to add or delete image channels to or from an existing PCIDSK database file.
See Also: PCIMOD, SHL, PCIADD2, PCIDEL2, LINK, FIMPORT, FEXPORT
Name Prompt Count Type FILE Database File Name 1-64 Char TEX1 Database Descriptive Text 1 0-64 Char TEX2 Database Descriptive Text 2 0-64 Char DBSZ Database Size: Pixels, Lines 2 Int PXSZ Pixel Ground-Size in Metres 0-2 Real DBNC No. of Channels: 8U,16S,16U,32R 1-4 Int DBLAYOUT Data Layout: PIXEL/BAND/FILE/TILED 0-64 Char
EASI>FILE="filespec"
EASI>TEX1=" string "
EASI>TEX2="string"
EASI>DBSZ=pixels,lines
PXSZ does not effect the pixel size in the georeference segment which remains as 1,1 until a bounds is specified for the image database.
EASI>PXSZ=Xsize,Ysize EASI>PXSZ= | defaults to 1 by 1
EASI>DBNC= 8bit,16bitsigned,16bitunsigned,32bitreal 8bit is the number of 8-bit unsigned integer channels signedint is the number of 16-bit signed integer channels unsignedint is the number of 16-bit unsigned integer channels real is the number of 32-bit real channelsThe following specifies six 16-bit signed channels:
EASI>DBNC=0,6The following specifies four channels, one of each type:
EASI>DBNC=1,1,1,1
EASI>DBLAYOUT="BAND" | Band interleaved
EASI>DBLAYOUT="PIXEL" | Pixel interleaved
EASI>DBLAYOUT="FILE" | File interleaved
EASI>DBLAYOUT="TILED" | Tiled, default tile size, no compr.
EASI>DBLAYOUT="TILED JPEG" | Tiled, with JPEG compression
EASI>DBLAYOUT="TILED256 RLE" | Tiled, with RLE compression and
256x256 pixel tiles.
EASI>DBLAYOUT= | defaults to BAND
The choice of layout is primarily based on performance. BAND
interleaved stores all the data for one band together, and gives
superior performance when not all bands are being accessed at all
times. PIXEL interleaved stores the data for all bands at a
particular pixel, together, and may give somewhat improved
performance when all bands are being utilized at once. FILE
interleaved is similar to BAND interleaved, but the image channel
data is stored in external files (one file per band).NOTE: BAND interleave is not supported for file over 2G. If the file is over 2G or will be over 2G, PIXEL interleave is recommended.
Tiled files have the image organized in many square subimages, and can be much faster to access when only a subarea is being extracted, such as in file viewing. Tiling is also the only format which supports compression formats, with the default being no compression. JPEG compression is a lossy compression, and is normally suitable for continuous images such as airphotos. RLE (Run Length Encoding) compression is lossless, but will only give good compression for images where long sequences of pixels have the same value, as typically happens in pseudo-coloured, or thematic images.
The default is BAND interleaved, but all layouts are equally acceptable to the full EASI/PACE system.
Disk space is allocated for a specified number of 8-bit unsigned, 16-bit signed, 16-bit unsigned, and 32-bit real image channels (DBNC) in either pixel-interleaved or band-interleaved mode (DBLAYOUT). The total number of channels cannot exceed 4096.
Creating a database file with no channels (DBNC=0) implies that the database file will be used only for storing segment data.
All image channels have the same number of pixels per line and lines per image (DBSZ). A database file can have up to 99 999 999 pixels per line (DBSZ(1)) and 99 999 999 lines per image (DBSZ(2)). It should be noted that the PCIDSK file is limited to being 2GB in size. DBSZ must always be specified, even if no image channels are on the file (DBNC=0). DBSZ is used to determine the size of bitmap segments, which may be added to the file later.
A database file can store a maximum of 1024 segments (any type). The first segment on the database file is always a georeferencing segment (type 150), containing the default identity transform.
CIM does not clear or write any data on the database channels. Initially, all database channels contain garbage, which can be overwritten later by other programs.
Descriptive text (TEX1,TEX2) pertaining to the image can be saved on the database file.
The horizontal and vertical dimensions of a single pixel (PXSZ) can be set in metres. This pixel size is used by other programs for calculating the area covered by a given part of the image. The default pixel size is 1 by 1 metres. The database pixel size can be modified by APS (if the database is not georeferenced) or by the GEOSET program (if the database is georeferenced).
The layout of image information (DBLAYOUT) on disk can either be PIXEL (for pixel interleaving), BAND (for band interleaving), FILE (for FILE interleaved), or TILED.
The choice of layout is primarily based on performance. BAND interleaved stores all the data for one band together, and gives superior performance when not all bands are being accessed at all times. PIXEL interleaved stores data the data for all bands at a particular pixel together, and may give somewhat improved performance when all bands are being utilized at once. FILE interleaved is similar to BAND interleaved, but the image channel data is stored in external files (one file per band).
NOTE: BAND interleave is not supported for file over 2G. If the file is over 2G or will be over 2G, PIXEL interleave is recommended.
Tiled files have the image organized in many square subimages, and can be much faster to access when only a subarea is being extracted, such as in file viewing. Tiling is also the only format which supports compression formats, with the default being no compression. JPEG compression is a lossy compression, and is normally suitable for continuous images such as airphotos. RLE (Run Length Encoding) compression is lossless, but will only give good compression for images where long sequences of pixels have the same value, as typically happens in pseudo-coloured, or thematic images.
Also note that no space is allocated for image data when a TILED format is created. The space on disk is consumed when an image is actually written to the file. This means that you may successfully create a file with CIM, but have later programs fail when they attempt to write to the file.
EASI>FILE="demo.pix" | File name EASI>TEX1="Demo Image" | Descriptive text EASI>TEX2= EASI>DBSZ=512,512 | 512 pixels by 512 lines EASI>PXSZ=30,50 | 30 by 50 metre resolution EASI>DBNC=6,0,0,3 | 6 8-bit and 3 32-bit channels EASI>DBLAYOUT="PIXEL" | pixel interleaving EASI>RUN CIM