MVC -- CCRS JSC Tape to Video Transfer

Transfers image data from any CCRS LANDSAT magnetic tape (including DICS format) to the video display.

PARAMETERS

MVC is controlled by the following global parameters: 

Name     Prompt                                  Count     Type
MTIC     Mag Tape Input Channel List             1-16      Int
VDOC     Video Output Channel List               1-16      Int
MTIW     Mag Tape Input Window                   0-4       Int
VDOW     Video Output Window                     0-4       Int
STARTFIL Start File on Tape                      1         Int
MTCH     User Specified Magtape Characteristics  0-7       Int

MTIC

The PACE parameter MTIC represents a list of image channels that reside on the input tape: 

 EASI>MTIC=i,j,...,n             | integers, 1-16

VDOC

The PACE parameter VDOC represents the video output channels where the input channel data is transferred from tape: 

 EASI>VDOC=i,j,...,m             | integers, 1-16

MTIW

The PACE parameter MTIW represents a window on tape that will be transferred to the image database: 

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

VDOW

The PACE parameter VDOW represents a window on the video display where the data from magnetic tape will be transferred. 

 EASI>VDOW=Xoffset,Yoffset,Xsize,Ysize
 EASI>VDOW=                     | defaults to entire display

STARTFIL

Specifies the start file number on tape from which to start reading header and image data. If STARTFIL is greater than one, the program rewinds the tape and advances to the specified file. STARTFIL must be set to the file number required by MSH program to print tape header report. 

 EASI>STARTFIL=1              | read first file on tape
 EASI>STARTFIL=n              | read nth file on tape
where STARTFIL is set to 1,4,7,10,..., for images 1,2,3,4.., on tape. The formula for STARTFIL is 3*n-2 where `n' is the start image number on tape. This is necessary because there are normally three "files" per image on tape. The first two are headers; the last is the imagery.

MTCH

This is a user specified magnetic tape characteristics parameter. It contains up to seven entries: 

        MTCH(1) = number of pixels per line 
        MTCH(2) = number of lines per image
        MTCH(3) = number of channels
        MTCH(4) = record size in bytes
        MTCH(5) = number of ancillary bytes 
        MTCH(6) = number of files to skip to image data 
        MTCH(7) = number of bits per pixel value
If any of the entries are specified, then these values will override the values that are read off the tape header.

DETAILS

MVC transfers image data from any set of bands on a CCRS LANDSAT tape (MTIC) to any set of image planes on a video display (VDOC).

Any arbitrary rectangular window on tape (MTIW) can be transferred to any arbitrary rectangular window on the display (VDOW). Shrinking and/or zooming is automatically performed. By default, the whole tape image is transferred, filling the entire display.

The record length in bytes times the number of channels on tape must be less than or equal to 32256.

Tape source headers are sometimes filled with erroneous data. In order to avoid problems associated with this situation, the user can employ the values stored in the parameter MTCH in PRM.PRM to override source header values. However, the values in MTCH must be greater than zero if the user wants to override the header value. Otherwise, the header value is used. If the user wishes to ensure that the header values are used, then he must type: 

 EASI> MTCH=
The following elements of MTCH can be employed to override the header values: 

        MTCH(1)  : number of pixels per line
        MTCH(2)  : number of lines on tape
        MTCH(3)  : number of channels on tape
        MTCH(4)  : record length in bytes
        MTCH(5)  : number of ancillary bytes 
        MTCH(6)  : number of files to skip to image data 
        MTCH(7)  : number of bits per pixel value
For example, if (i) MTCH(1) = 1 (ii) MTCH(2) = 0 (iii) MTCH(3) = 0 and the corresponding header values are (i) 0 (ii) 1 (iii) 0, then:

(i) MTCH(1) overrides header since its value is greater than zero.

(ii) Header value is used since MTCH(2) is NOT greater than zero, AND header value is legal (greater than zero).

(iii) Error message is given since both values of MTCH(3) AND header are equal to zero.

More information on CCRS format can be found in the documentation for program IMC. 

 A TAPE MUST BE MOUNTED ON THE TAPE DRIVE BEFORE MVC CAN BE RUN.
 CLEANING THE TAPE HEADS IS RECOMMENDED TO MINIMIZE THE CHANCE
 OF TAPE READ ERRORS.

EXAMPLE

 EASI>MTIC=1,2,3
 EASI>VDOC=1,2,3
 EASI>MTIW=0,0,512,512
 EASI>VDOW=MTIW
 EASI>STARTFIL=4        | get 2nd image on tape
 EASI>MTCH=             | override header value for
 EASI>MTCH(2)=630       | number of lines on image
 EASI>RUN MVC
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