ERDASRD -- Read Image from ERDAS File

Transfers (reads) data from ERDAS format file resident on disk to an existing PCIDSK image database file.

ERDASRD copies a subset of ERDAS image data to an existing PCIDSK file, excluding georeferencing data, whereas ERDASCP creates a new PCIDSK file, and copies all ERDAS data, including georeferencing data, to the new PCIDSK file.

Progress of this program can be monitored. See MONITOR section.

See Also: ERDASCP, ERDASHD, ERDASWR

PARAMETERS

ERDASRD is controlled by the following global parameters: 

Name     Prompt                                  Count     Type
ERDASFIL ERDAS File Name                         1-64      Char
FILO     Database Output File Name               1-64      Char
DBIC     ERDAS file Input Channel List           1-1024    Int
DBOC     Database Output Channel List            1-1024    Int
DBIW     ERDAS file Input Window                 0-4       Int
DBOW     Database Output Window                  0-4       Int
ERDASTRA ERDAS Trailer File Name                 0-64      Char

ERDASFIL

Specifies the ERDAS file name. 

 EASI>ERDASFIL="file_specification"
The file extension must be either `.lan' or `.gis'

FILO

Specifies the name of the PCIDSK file to which image data is to be written. FILO must exist before running ERDASRD. 

 EASI>FILO="file_specification"
ERDASRD does NOT update the georeference segment on FILO with the georeference information from ERDASFIL. Program ERDASCP would copy the georeference information from ERDASFIL to the georeference segment on FILO.

DBIC

Specifies the input channels to be read from FILI. 

 EASI>DBIC=m,n,...,p

DBOC

Specifies the output channels to be written to FILO. 

 EASI>DBOC=i,j,...,l

DBIW

Specifies the window of data to be extracted from the input channel. 

 EASI>DBIW=Xoffset,Yoffset,Xsize,Ysize
 EASI>DBIW=                     | defaults to entire image

DBOW

Specifies the window in output channel in which image is to be embedded. 

 EASI>DBOW=Xoffset,Yoffset,Xsize,Ysize
 EASI>DBOW=                     | defaults to entire image

ERDASTRA

Specifies processing a trailer file for the ERDAS image file.

An ERDAS .GIS file of classified imagery may have a .TRL file associated with it. If the .TRL file has a pseudo-colour table defined, this data may be copied to a pseudo-colour table segment created on FILO. 

 EASI>ERDASTRA="OFF"            | .TRL file NOT processed
 EASI>ERDASTRA="ON"             | if the ERDASFIL suffix is .GIS, a 
                                | .TRL format file may be processed 
                                | e.g. if ERDASFIL = "irvine.gis" and
                                | ERDASTRA = "on", then "irvine.trl" 
                                | is processed
 EASI>ERDASTRA="file"           | If ERDASFIL suffix is .GIS, process a
                                | .TRL format file named "file"
 EASI>ERDASTRA=                 | Default, .TRL file NOT processed
An ERDAS .LAN file of unclassified imagery may have a .STA file of grey-level statistics associated with it. This information is not stored by EASI/PACE, so .STA files are not processed with programs ERDASCP or EDASRD. The format for the .TRL and .STA files are described in the TRAILER_FORMAT section in program ERDASWR.

DETAILS

ERDASRD converts an ERDAS image file (ERDASFIL) resident on disk (floppy, optical, hard) into a PCIDSK image database file (FILO). Up to 1024 image channels (DBIC) may be converted to PCIDSK image channels (DBOC) at a time. Any arbitrary rectangular window (DBIW) may be extracted from the input file and inserted into a rectangular window (DBOW) on the output file. If the input and output windows do not have the same dimensions, shrinking or zooming is done automatically. ERDASTRA can be defined if the image file is a .GIS file and there is a pseudo-colour table to be read from an associated .TRL trailer file.

If the number of pixels per line times the number of bands on the disk file exceeds 51200 bytes on PC systems or 262144 bytes on all other systems, an error message "Work buffer too small" is printed, and the program terminates.

The formats for ERDAS files supported are listed in program ERDASWR. The format of the image files is in the IMAGE_FORMAT section. The format of the image trailer files is in the TRAILER_FORMAT section.

MONITOR

Program progress can be monitored by printing the percentage of completed processing in odometer fashion. A system parameter, MONITOR, controls this activity: 

 EASI>MONITOR="ON"           | turn monitor ON  (default)
 EASI>MONITOR="OFF"          | turn monitor OFF (recommended if
                             | running in batch/background mode)

EXAMPLE

Transfer image from an ERDAS file (irvine.lan) to an existing PCIDSK database file. Image data on the ERDAS file are organized as 512 pixels by 512 lines by 5 bands, preceded by a 128-byte header. The band interleaving mode is BIL. No trailer file is read. 

 EASI>FILE="local.pix"
 EASI>DBSZ=512,512
 EASI>DBNC=5
 EASI>RUN CIM

 EASI>ERDASFIL="irvine.lan"
 EASI>FILO="local.pix"
 EASI>DBIC=1,-5                 ! Range of channels {1,2,3,4,5}
 EASI>DBOC=1,-5                 ! Range of channels {1,2,3,4,5}
 EASI>DBIW=
 EASI>DBOW=
 EASI>ERDASTRA=
 EASI>RUN ERDASRD
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