MIANCON -- Peru ANCON GOES Tape to Database Transfer

Reads GOES weather satellite data distributed on 9-track tape by the GOES Satellite Station in Peru.

This program reads the OLD Ancon tape format and the NEW Ancon format. The old Ancon format was used to produce tapes until the end of October 1989. The new Ancon format is used for tapes after this date.

The exact format is given in a document titled `ARCHIVED DATA DESCRIPTION' dated December 15, 1987. This document appears to have been written by MacDonald Dettwiler and Associates Ltd. (Richmond, B.C., Canada) and seems to be part of a larger documentation set about METSAT.

PARAMETERS

MIANCON is controlled by the following global parameters: 

Name     Prompt                                  Count     Type
FILE     Database File Name                      1-64      Char
MTIC     Mag Tape Input Channel List             1-16      Int
DBOC     Database Output Channel List            1-16      Int
MTIW     Mag Tape Input Window                   0-4       Int
DBOW     Database Output Window                  0-4       Int
STARTFIL Start File on Tape                      1         Int

FILE

Specifies the name of the PCIDSK image database to receive output imagery from MIANCON. 

 EASI>FILE="...filename..."

MTIC

Specifies the channels to read off tape. 

 EASI>MTIC=i,...,k
Though the number and type of channels is not always the same for each tape, most tapes have the following setup: 

 Channel 1   Base map
 Channel 2   Visual Data
 Channel 3   IR Band A
 Channel 4   IR Band B
 Channel 5   IR Band C

DBOC

Specifies the output channels on the database file which should receive the data. 

 EASI>DBOC=l,...,m

MTIW

Specifies a rectangular subset of the image on tape to be used for input. 

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

DBOW

Specifies a rectangular subset of the image channel in the output database to receive imagery. 

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

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
Each file is a single GOES scene. The number of scenes on tape can vary, but usually there are between 5 and 10.

DETAILS

MIANCON will read data from both the old and new Ancon tape formats. The type of tape is automatically detected.

Note: At the time this program was written, complete details for the new Ancon format were not available. The code written was done by interpreting the structure of sample tapes. It is possible that these samples may not have described all the possible variations and that MIANCON will fail on some new Ancon tapes. Any tapes in the old format should work properly.

Any arbitrary rectangular window on tape (MTIW) can be transferred to any arbitrary rectangular window on the database (DBOW). If no output window is specified, then the window is defaulted to the full-size window of the database channel. Shrinking and/or zooming is automatically performed.

Any set of channels on tape (MTIC) can be read and output to any set of channels on the PCIDSK database (DBOC).

Any file (image) on tape (STARTFIL) can be specified. MIANCON will advance or rewind to the selected file before transferring.

The images on tape are usually one of the following sizes: 512 pixels by 512 lines; 1024 by 1024; or 4096 by 4096. The 1024 by 1024 size seems to be most common.

Typically, there are 5 channels of data for each scene or file: a basemap; a visual channel; and 3 IR (infra red) channels.

The basemap channel is not actually data from the satellite but is an overlay giving landform and gridding outlines. It is useful in locating regions if cloud cover is especially heavy.

The visual channel contains the highest resolution data.

The three IR channels are lower resolution than the visual channel and may look grainy and without features if shown on a display. Overlaying the basemap is useful for these channels. 

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

NEW TAPE LAYOUT

The new tape format seems to be so complicated and poorly documented that it defies a simple description.

The exact format may be available from MacDonald Dettwiler and Associates Ltd. (Richmond, B.C., Canada) and seems to be part of a larger documentation set about METSAT. No specific title was known by PCI at the time this program was written.

To read this format, gross assumptions were made about the tape structure based on dumping the example tapes using tape utilities. This is not a very robust method, and it is possible that some new tapes produced by Ancon may not be readable.

OLD TAPE LAYOUT

This section gives a rough idea of the layout of the data on the tape distributed by the Peruvian Ancon GOES satellite station for the old format (to October 1989).

The exact format is given in a document titled `ARCHIVED DATA DESCRIPTION' dated December 15, 1987. This document appears to have been written by MacDonald Dettwiler and Associates LTD (Richmond, B.C., Canada) and seems to be part of a larger documentation set about METSAT.

The first file on the tape contains the volume description used by VAX computers. Records are 80 bytes long.

Each of the following files contains a GOES scene. All records in the scene are 13312 bytes long. These records come in two forms: administration records and data records. Administration records hold information describing the data held for the scene. Data records hold the actual information. In general, data is band sequential with each data record holding more than one image line.

Each file is separated by an End of File mark (EOF). The entire tape is ended with two EOFs in a row.

The following shows one possible example of a tape layout: 

 Record     Record Description
  Size  

     80     Volume description                  | 
     80     Volume description                  | Volume header
     80     Volume description                  | 

     * E O F *

  13312     Feature Set administration          |
  13312    [Ancillary Data administration]      |
  13312     Feature administration (Basemap)    |
  13312    Data                                 |
   ...                                          |
  13312     Feature administration (Visual)     |
  13312    Data                                 |
   ...                                          |
  13312     Feature administration (IR Band A)  |
  13312    Data                                 | File 1
   ...                                          |
  13312     Feature administration (IR Band B)  |
  13312    Data                                 |
   ...                                          |
  13312     Feature administration (IR Band C)  |
  13312    Data                                 |
   ...                                          |
  13312    Data                                 |

     * E O F *

  13312     Feature Set administration          |
  13312    [Ancillary Data administration]      |
  13312     Feature administration (Basemap)    | File 2
  13312    Data                                 |
   ...                                          |

     * E O F *
     * E O F *

EXAMPLE

The user has received a tape from the GOES satellite station in Peru and wishes to read the data from the third file on the tape into a PCIDSK file so it can be viewed and processed.

The first step is to create a PCIDSK file to hold the GOES data when it is read from tape. GOES data is usually 1024 pixels by 1024 lines in size with 5 channels of data (basemap, visual and three IR bands). Database files are created using the program CIM. 

 EASI> FILE = "GOES.PIX"
 EASI> TEX1 = "Goes picture of Peru"
 EASI> DBSZ = 1024,1024
 EASI> DBNC = 5
 EASI> RUN CIM
Now the tape can be read using MIANCON. Ensure that the tape is mounted on the tape drive and that the drive is on-line. An overview of the 5 channels of data in the GOES scene on file 3 will be read. 

 EASI> MTIC = 1,2,3,4,5
 EASI> DBOC = 1,2,3,4,5
 EASI> MTIW =
 EASI> DBOW =
 EASI> STARTFIL = 3
 EASI> RUN MIANCON
As MIANCON runs, it will print out the actual size of the GOES image and each channel as it is read. If any errors occur, the user will be informed and can use this printed information to correct the parameters for MIANCON before attempting to do the read again.

Once the data has been transferred it can be displayed using IVI.

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