grdvolume(1) Calculating volume under a surface within a contour


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


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


No space between the option flag and the associated arguments.
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.
Also add in the volume from the level of the contour down to base [Default base is contour].
Convert degrees to meters, append k for km [Default is Cartesian].
Use curvature minimum rather than maximum height to find best contour value (when contour search is selected with -C).
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.
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).
Optionally subtract shift before scaling data by fact. [Default is no scaling]. (Numbers in -C, -L refer to values after this scaling has occurred).


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


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