## NAME

m.dmaUSGSread - Extracts digital terrain elevation data (DTED) produced by the Defense Mapping Agency (DMA) but supplied by the USGS (in a different tape format) on 1/2-inch magnetic tape.
(GRASS Data Import/Processing Program)

## SYNOPSIS

dd [if=tapedev] ibs=input-block-size | m.dmaUSGSread top=value bottom=value left=value right=value output=name logfile=name

## DESCRIPTION

m.dmaUSGSread extracts digital terrain elevation data (DTED) that was produced by the Defense Mapping Agency (DMA) but bought from the USGS; these two agencies distribute the same data in a slightly different tape formats. This program requires the use of the UNIX command dd to read the 1/2-inch magnetic tape. m.dmaUSGSread should be used prior to using the GRASS programs m.rot90 and r.in.ll.

Parameters for the UNIX dd command are listed below.

if=tapedev
  The path name of the tape drive from which input will be taken (usually `/dev/rmt0`).
ibs=input-block-size
  The physical blocking value of the data on tape, usually written on the tape spool. If this value is unknown, run m.examine.tape prior to running m.dmaUSGSread.

  Parameters for m.dmaUSGSread are listed below.

top=value
  Beginning row number of data.
  Options: 1-1201
bottom=value
  Ending row number of data.
  Options: 1-1201
left=value
  Beginning column number of data.
  Options: 1-1201
right=value
  Ending column number of data.
  Options: 1-1201
output=name
  Name of the output file to hold the extracted DEM data.
logfile=name
  Name of a file to hold related information about the extracted data.

  ## EXAMPLE:

  For example, the command:
    dd if=/dev/rmt0 ibs=10240 | \
    m.dmaUSGSread top=1 bottom=400 left=1 right=500 \
    output=dem logfile=log
  will extract data from `/dev/rmt0` and put the first 400 rows and first 500 columns into the file dem located in the user's current directory.

  ## SEE ALSO

  Options for Acquiring Elevation Data, by Stuart Bradshaw, (ADP Report N-87/22, USACERL, 1988).

  DTED and DEM Elevation Data Extraction, by Stuart Bradshaw, Mary Martin, and Chester Kos (ADP Report N-87/22, USACERL, 1988).

  and the UNIX manual entry for dd

  g.region
  m.dted.examine
  m.dted.extract
  m.examine.tape
  m.region.ll
  m.rot90
  r.describe
  r.in.ll
  r.rescale
  r.slope.aspect

  ## AUTHORS

  James Farley, Arkansas Archeological Survey, University of Arkansas
  Michael Shapiro, U.S.Army Construction Engineering Research Laboratory

  Last changed: $Date: 2002/01/25 05:45:33 $