grdvolume(1) [debian man page]

GRDVOLUME(l)															      GRDVOLUME(l)

NAME

       grdvolume - Calculating volume under a surface within a contour

SYNOPSIS

       grdvolume grdfile [ -Ccval or -Clow/high/delta ] [ -Lbase ] [ -Rwest/east/south/north[r] ] [ -S[k] ] [ -T ] [ -V[l] ] [ -Zfact[/delta] ]

DESCRIPTION

       grdvolume  reads a 2-D binary grd file and calculates the volume contained between the surface and the plane specified by the given contour
       (or zero if not given).	Alternatively, specify a range of contours to be tried and grdvolume will determine the volume and area inside the
       contour	for  all  contour values. The contour that produced the maximum mean height (volume/area) is reported as well. This feature may be
       used with grdfilter in designing an Optimal Robust Separator [Wessel, 1998].

       grdfile
	      The name of the input 2-D binary grd file.

OPTIONS

       No space between the option flag and the associated arguments.

       -C     find area and volume inside the cval contour. Alternatively, search using all contours from low to high in steps of delta.  [Default
	      returns entire area and volume of grid]. The area is measured in the plane of the countour.

       -L     Also add in the volume from the level of the contour down to base [Default base is contour].

       -S     Convert degrees to meters, append k for km [Default is Cartesian].

       -T     Use curvature minimum rather than maximum height to find best contour value (when contour search is selected with -C).

       -R     west,  east,  south,  and  north specify the Region of interest. To specify boundaries in degrees and minutes [and seconds], use the
	      dd:mm[:ss] format. Append r if lower left and upper right map coordinates are given instead of wesn.

       -V     Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].  Append l to see  all  the  results  for
	      each contour level tested (when contour search has been selected).

       -Z     Optionally subtract shift before scaling data by fact. [Default is no scaling].  (Numbers in -C, -L refer to values after this scal-
	      ing has occurred).

EXAMPLES

       To determine the volume in km^3 under the surface hawaii_topo.grd (height in km), try

       grdvolume hawaii_topo.grd -Sk

       To find the volume between the surface peaks.grd and the contour z = 250, use

       grdvolume peaks.grd -Sk -C250

       To search for the contour, between 100 and 300 in steps of 10, that maximizes the ratio of volume to surface area for the  file	peaks.grd,
       use

       grdvolume peaks.grd -Sk -C100/300/10 > results.d

       To see the areas and volumes for all the countours in the previous example, try

       grdvolume peaks.grd -Sk -Vl -C100/300/10 > results.d

SEE ALSO

       gmt(1gmt), grdfilter(1gmt)

REFERENCES

       Wessel, P., 1998, An empirical method for optimal robust regional-residual separation of geophysical data, Math. Geol., 30(4), 391-408.

								    1 Jan 2004							      GRDVOLUME(l)

Check Out this Related Man Page

GRDEDIT(l)																GRDEDIT(l)

NAME

       grdedit - Modifying the header in a 2-D grdfile

SYNOPSIS

       grdedit grdfile [ -A ] [ -Dxunit/yunit/zunit/scale/offset/title/remark ] [ -Rwest/east/south/north[r] ] [ -S ] [ -V ]

DESCRIPTION

       grdedit	reads  the  header  information  in a binary 2-D grdfile and replaces the information with values provided on the command line [if
       any]. As an option, global, geographical grids (with 360 degrees longitude range) can be rotated in the east-west direction.  grdedit  only
       operates on files containing a grdheader.
	       No space between the option flag and the associated arguments. Use upper case for the option flags and lower case for modifiers.

       grdfile
	      Name of the 2-D grdfile to modify

OPTIONS

       -A     If necessary, adjust the file's x_inc, y_inc to be compatible with its domain (or a new domain set with -R).  Older gridfiles (i.e.,
	      created prior to GMT 3.1) often had excessive slop in' x_inc, y_inc and an adjustment is necessary. Newer  files	are  created  cor-
	      rectly.

       -D     Give  new values for xunit, yunit, zunit, scale, offset, title, and remark.  To leave some of the values untouched, specify = as the
	      new value.

       -R     west, east, south, and north specify the Region of interest. To specify boundaries in degrees and minutes  [and  seconds],  use  the
	      dd:mm[:ss]  format.  Append  r if lower left and upper right map coordinates are given instead of wesn.  The new w/e/s/n values will
	      replace those in the grid, and the x_inc, y_inc values are adjusted, if necessary.

       -S     For global, geographical grids only. Grid values will be shifted laterally according to the new borders given in -R.

       -V     Selects verbose mode, which will send progress reports to stderr [Default runs "silently"].

EXAMPLES

       Let us assume the file data.grd covers the area 300/310/10/30. We want to change the boundaries from geodetic longitudes to geographic  and
       put a new title in the header. We accomplish this by

       grdedit data.grd -R-60/-50/10/30 -D=/=/=/=/=/"Gravity Anomalies"/=

       The grid world.grd has the limits 0/360/-72/72. To shift the data so that the limits would be -180/180/-72/72, use

       grdedit world.grd -R-180/180/-72/72 -S

       The file junk.grd was created prior to GMT 3.1 with incompatible -R and -I arguments. To reset the x- and y-increments we run

       grdedit junk.grd -A

SEE ALSO

       gmt(1gmt), grd2xyz(1gmt), xyz2grd(1gmt)

								    1 Jan 2004								GRDEDIT(l)

Linux and UNIX Man Pages

grdvolume(1) [debian man page]

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