grdview
grdview - Create 3-D perspective grayshaded/colored image
or mesh from a 2-D grd file
SYNOPSIS
grdview relief_file -Jparameters [ -Btickinfo ] [-Ccpt
file] [ -Eview_az/view_el ] [ -Gdrapefile] [ -Iintensfile]
[ -K ] [ -L[flags] ] [ -Nlevel[/r/g/b]] [ -O ] [ -P ] [
-Qtype ] [ -Rwest/east/south/north/zmin/zmax[r] ] [
-Ssmooth ] [ -T[s] ] [ -U[/dx/dy/][label] ] [ -V ] [
-Wtype/pen ] [ -Xx-shift ] [ -Yy-shift ] [ -Zzlevel ] [
-ccopies ]
DESCRIPTION
grdview reads a 2-D gridded file and produces a 3-D per
spective plot by drawing a mesh, painting a col
ored/grayshaded surface made up of polygons, or by scan
line conversion of these polygons to a rasterimage.
Options include draping a data set on top of a surface,
plotting of contours on top of the surface, and apply
artificial illumination based on intensities provided in a
separate grd file.
relief_file
2-D gridded data set to be imaged (the relief of
the surface).
-J Selects the map projection. Scale is UNIT/degree,
1:xxxxx, or width in UNIT (upper case modifier).
UNIT is cm, inch, or m, depending on the MEA
SURE_UNIT setting in .gmtdefaults, but this can be
overridden on the command line by appending the c,
i, or m to the scale/width value.
CYLINDRICAL PROJECTIONS:
-Jclon0/lat0/scale (Cassini)
-Jjlon0/scale (Miller)
-Jmscale (Mercator - Greenwich and Equator as ori
gin)
-Jmlon0/lat0/scale (Mercator - Give meridian and
standard parallel)
-Joalon0/lat0/azimuth/scale (Oblique Mercator -
point and azimuth)
-Joblon0/lat0/lon1/lat1/scale (Oblique Mercator -
two points)
-Joclon0/lat0/lonp/latp/scale (Oblique Mercator -
point and pole)
-Jqlon0/scale (Equidistant Cylindrical Projection
(Plate Carree))
-Jtlon0/scale (TM - Transverse Mercator, with Equa
tor as y = 0)
-Jtlon0/lat0/scale (TM - Transverse Mercator, set
-Jylon0/lats/scale (Basic Cylindrical Projection)
AZIMUTHAL PROJECTIONS:
-Jalon0/lat0/scale (Lambert).
-Jelon0/lat0/scale (Equidistant).
-Jflon0/lat0/horizon/scale (Gnomonic).
-Jglon0/lat0/scale (Orthographic).
-Jslon0/lat0/[slat/]scale (General Stereographic)
CONIC PROJECTIONS:
-Jblon0/lat0/lat1/lat2/scale (Albers)
-Jdlon0/lat0/lat1/lat2/scale (Equidistant)
-Jllon0/lat0/lat1/lat2/scale (Lambert)
MISCELLANEOUS PROJECTIONS:
-Jhlon0/scale (Hammer)
-Jilon0/scale (Sinusoidal)
-Jk[f|s]lon0/scale (Eckert IV (f) and VI (s))
-Jnlon0/scale (Robinson)
-Jrlon0/scale (Winkel Tripel)
-Jvlon0/scale (Van der Grinten)
-Jwlon0/scale (Mollweide)
NON-GEOGRAPHICAL PROJECTIONS:
-Jp[a]scale[/origin] (polar (theta,r) coordinates,
optional a for azimuths and offset theta [0])
-Jxx-scale[l|ppow][/y-scale[l|ppow]] (Linear, log,
and power scaling)
More details can be found in the psbasemap man
pages.
-Jz Sets the vertical scaling (for 3-D maps). Same syn
tax as -Jx.
OPTIONS
No space between the option flag and the associated argu
ments.
-B Sets map boundary tickmark intervals. See psbasemap
for details.
-C name of the color palette file. Must be present if
you want (1) mesh plot with contours (-Qm), or (2)
shaded/colored perspective image (-Qs or -Qi). For
-Qs: You can specify that you want to skip a z-
slice by setting red = -; to use a pattern give red
= P|pdpi/pattern[:Fr/g/b[Br/g/b]].
-G Drape the image in drapefile on top of the relief
provided by relief_file. [Default is relief_file].
Note that -Jz and -N always refers to the
relief_file. The drapefile only provides the infor
mation pertaining to colors.
-I Gives the name of a grdfile with intensities in the
(-1,+1) range. [Default is no illumination].
-K More PostScript code will be appended later
[Default terminates the plot system].
-L Boundary condition flags may be x or y or xy indi
cating data is periodic in range of x or y or both,
or flags may be g indicating geographical condi
tions (x and y are lon and lat). [Default uses
"natural" conditions (second partial derivative
normal to edge is zero).] If no flags are set, use
bilinear rather than the default bicubic resampling
when draping is required.
-N Draws a plane at this z-level. If the optional
r/g/b is provided, the frontal facade between the
plane and the data perimeter is colored.
-O Selects Overlay plot mode [Default initializes a
new plot system].
-P Selects Portrait plotting mode [GMT Default is
Landscape, see gmtdefaults to change this].
-R west, east, south, and north specify the Region of
interest. To specify boundaries in degrees and min
utes [and seconds], use the dd:mm[:ss] format.
Append r if lower left and upper right map coordi
nates are given instead of wesn. This option may
be used to indicate the range used for the 3-D axes
[Default is region given by the relief_file]. You
may ask for a larger w/e/s/n region to have more
room between the image and the axes. A smaller
region than specified in the relief_file will
result in a subset of the grid.
-Q Select one of three settings: 1. Specify m for mesh
plot [Default], and optionally append /r/g/b for a
different mesh paint [white]. 2. Specify s for
surface plot, and optionally append m to have mesh
lines drawn on top of surface. 3. Specify i for
image plot, and optionally append the effective dpi
resolution for the rasterization [100]. For any of
these choices, you may force a monochrome image by
-S Smooth the contours before plotting (see grdcon
tour) [Default is no smoothing]
-T Plot image without any interpolation. This involves
converting each node-centered bin into a polygon
which is then painted separately. Append s to skip
nodes with z = NaN. This option is useful for cate
gorical data where interpolating between values is
meaningless.
-U Draw Unix System time stamp on plot. User may spec
ify where the lower left corner of the stamp should
fall on the page relative to lower left corner of
plot. Optionally, append a label, or c (which will
plot the command string.). The GMT parameters
UNIX_TIME and UNIX_TIME_POS can affect the appear
ance; see the gmtdefaults man page for details.
-V Selects verbose mode, which will send progress
reports to stderr [Default runs "silently"].
-Wc Draw contour lines on top of surface or mesh (not
image). Append pen attributes used for the con
tours. [Default: width = 3, color = 0/0/0, texture
= solid].
-Wm Sets the pen attributes used for the mesh.
[Default: width = 1, color = 0/0/0, texture =
solid]. You must also select -Qm or -Qsm for mesh
lines to be drawn.
-X -Y Shift origin of plot by (x-shift,y-shift). Prepend
a for absolute coordinates; the default (r) will
reset plot origin.
-Z Sets the z-level of the basemap [0].
-c Specifies the number of plot copies. [Default is 1]
EXAMPLES
To make a mesh plot from the file hawaii_grav.grd and
drawing the contours given in the color palette file
hawaii.cpt on a Lambert map at 1.5 cm/degree along the
standard parallels 18 and 24, with vertical scale 20
mgal/cm, and looking at the surface from SW at 30 degree
elevation, try
grdview hawaii_grav.grd -Jl18/24/1.5c -Chawaii.cpt
-Jz0.05c -Qm -N-100 -E225/30 -Wc > hawaii_grav_image.ps
To create a illuminated color perspective plot of the
marks every 5 units, with intensities provided by the file
intens.grd, and looking from the SE, try
grdview image.grd -Jx10.0c -Ccolor.rgb -Qs -E135/30 -Iin
tens.grd > image3D.ps
To make the same plot using the rastering option with dpi
= 50, try
grdview image.grd -Jx10.0c -Ccolor.rgb -Qi50 -E135/30
-Iintens.grd > image3D.ps
To create a color PostScript perspective plot of the grid
ded data set magnetics.grd, using the color palette file
mag_intens.cpt, draped over the relief given by the file
topography.grd, with Mercator map width of 6 inch and
tickmarks every 1 degree, with intensities provided by the
file topo_intens.grd, and looking from the SE, try
grdview topography.grd -JM6i -Gmagnetics.grd
-Cmag_intens.cpt -Qs -E140/30 -Itopo_intens.grd >
draped3D.ps
BUGS
For the -Qs option: PostScript provides no way of smoothly
varying colors within a polygon, so colors can only vary
from polygon to polygon. To obtain smooth images this way
you may resample the grdfile(s) using grdsample or use a
finer grid size when running gridding programs like sur
face or nearneighbor. Unfortunately, this produces huge
PostScript files. The alternative is to use the -Qi
option, which computes bilinear or bicubic continuous
color variations within polygons by using scanline conver
sion to image the polygons.
SEE ALSO
gmt(l), grdcontour(l), grdimage(l), nearneighbor(l),
psbasemap(l), pscontour(l), pstext(l), surface(l)
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