NAME
m.dted.extract - Extracts digital terrain elevation data
(DTED - levels 1 and 2) produced and supplied by the Defense Mapping Agency
(DMA) on 1/2-inch magnetic tapes.
(GRASS Data Import/Processing Program)
SYNOPSIS
m.dted.extract
if=name
of=name
hf=name
n="string"
s="string"
e="string"
w="string"
DESCRIPTION
m.dted.extract
extracts DTED (Levels 1 and 2) digital terrain elevation data
produced by the Defense Mapping Agency (DMA) from 1/2-inch magnetic tapes
obtained from DMA.
OPTIONS
Data is read from the input file (if). If the user
does not specify any input file name on the command line,
the program assumes that input is coming from
/dev/rmt0. The extracted data is placed in the
output file (of). This program should be used in
conjunction with the programs
m.rot90 and
r.in.ll
to convert DTED data to GRASS
raster format.
Parameters:
- if=name
- The pathname of the tape device where the raw DTED data exists
(default is /dev/rmt0)
- of=name
- The full pathname of the output file into which the extracted tape data is
to be copied
- hf=name
- The full pathname of a file to contain descriptive information about
the extracted data; should be placed in the same directory as the output file
- n="string"
- North latitude value defining the boundaries of the extraction geographic
region
(format: dd.mm.ss[n|s])
- s="string"
- South latitude value defining the extraction geographic region
(format: dd.mm.ss[n|s])
- ea="string"
- East longitude value defining the extraction geographic region
(format: dd.mm.ss[e|w])
- w="string"
- West longitude value defining the extraction geographic region
(format: dd.mm.ss[e|w])
The n, s, e and w
parameters define a
geographic region that should completely encompass the data
set. dd.mm.ss are degree, minute, and second
values. Only data that falls within this defined
geographic region will be extracted from the tape.
EXAMPLE
The command line:
-
m.dted.extract if=/dev/rmt0 of=dted.out hf=dted.head
n=37.30.00n s=37.15.00n e=103.30.00w w=103.45.00w
will extract DTED data from /dev/rmt0,
store it in a file named dted.out,
and store some supporting information in the file dted.head.
Only data that falls within the geographic region
defined by the coordinates n, s, e and w
will be extracted.
NOTE
The user should examine the contents of the header file produced by
this program; it contains information needed as inputs to the
data rotation and raster file import programs
m.rot90
and
r.in.ll,
respectfully.
BUGS
The format of the header file for DTED Level 1 and 2 data was changed in 1987.
m.dted.extract and
m.dted.examine
only operate on DTED data containing pre-1987 headers.
DTED data containing the pre-1987 headers may be purchased
from the DMA upon request.
DIAGNOSTICS
Invalid requests are so designated.
SEE ALSO
Pursuance of Elevation Data, by
Stuart Bradshaw, USACERL
DTED and DEM Elevation Data
Extraction, by
Stuart Bradshaw, Mary Martin,
and Chester Kos,
USACERL
g.region
m.dmaUSGSread
m.dted.examine
m.examine.tape
m.region.ll
m.rot90
r.describe
r.in.ll
r.rescale
r.slope.aspect
AUTHOR
Michael Shapiro, U.S.Army Construction Engineering
Research Laboratory