NAME
grdview - Create 3-D perspective grayshaded/colored image or
mesh from a 2-D grd file
SYNOPSIS
grdview relief_file -Jparameters [ -Btickinfo ] [- Ccptfile]
[ - Dndec ] [ -Eview_az/view_el ] [ -Fred/green/blue ] [ -
Gdrapefile] [ -Iintensfile] [ - K ] [ - Mmeshpen] [ -
Nlevel[/r/g/b]] [ - O ] [ - P ] [ - Qtype ] [ -
Rwest/east/south/north/zmin/zmax[r] ] [ - Ssmooth ] [ -
U[/dx/dy/][label] ] [ -V ] [ -Wcontourpen ] [ -Xx-shift ] [
-Yy-shift ] [ -Zzlevel ] [ -ccopies ]
DESCRIPTION
grdview reads a 2-D gridded file and produces a 3-D perspec-
tive plot by drawing a mesh, painting a colored/grayshaded
surface made up of polygons, or by scanline 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 inch/degree,
1:xxxxx. or width in inch (upper case modifier).
CYLINDRICAL PROJECTIONS:
-Jclon0/lat0/scale (Cassini)
-Jmscale (Mercator - Greenwich and Equator as origin)
-Jmlon0/lat0/scale (Mercator - Give meridian and stan-
dard 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)
-Juzone/scale (UTM - Universal Transverse Mercator)
-Jylon0/lats/scale (Basic Cylindrical Projection)
AZIMUTHAL PROJECTIONS:
-Jalon0/lat0/scale (Lambert).
-Jelon0/lat0/scale (Equidistant).
-Jglon0/lat0/scale (Orthographic).
-Jslon0/lat0/scale (General Stereographic)
CONIC PROJECTIONS:
-Jblon0/lat0/lat1/lat2/scale (Albers)
-Jllon0/lat0/lat1/lat2/scale (Lambert)
MISCELLANEOUS PROJECTIONS:
-Jhlon0/scale (Hammer)
-Jilon0/scale (Sinusoidal)
-Jklon0/scale (Eckert VI)
-Jnlon0/scale (Robinson)
-Jrlon0/scale (Winkel Tripel)
-Jwlon0/scale (Mollweide)
NON-GEOGRAPHICAL PROJECTIONS:
-Jpscale (Linear projection for polar (theta,r) coordi-
nates)
-Jxx-scale[l|ppow][/y-scale[l|ppow]] (Linear, log, and
power scaling)
More details can be found in the psbasemap manpages.
-Jz Sets the vertical scaling (for 3-D maps). Same syntax
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).
-D Sets number of decimals used to specify color/gray in
PostScript output. Makes smaller output file at the
expense of less color resolution. E.g., 3 gives 1000,
2 gives 100, and 1 gives 10 choices each or r, g, and
b, values [3].
-E Sets the view point by specifying azimuth and eleva-
tion in degrees. [Default is 180/90]
-F Sets the color used for Frame and annotation. [Default
is black]
-G Drape the image in drapefile on top of the relief pro-
vided by relief_file. [Default is relief_file]. Note
that -Jz and -N always refers to the relief_file. The
drapefile only provides the information 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].
-M Sets the pen attributes used for the mesh. [Default:
width = 1, color = 0/0/0, texture = solid]
-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 minutes
[and seconds], use the dd:mm[:ss] format. Append r if
lower left and upper right map coordinates 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 dif-
ferent 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]. This option will apply a simple
clippath to avoid overwriting the background (since the
resulting image is rectangular). Depending on the pro-
jection this may backfire; if so turn clipping off by
using upper case I. For any of these choices, you may
force a monochrome image by appending g. Colors are
then converted to shades of gray using the (television)
YIQ transformation.
-S Smooth the contours before plotting (see grdcontour)
[Default is no smoothing]
-U Draw Unix System time stamp on plot. User may specify
where the lower left corner of the stamp should fall on
the page relative to lower left corner of plot in inch
[Default is (-0.75,-0.75)]. Optionally, append a
label, or c (which will plot the command string.)
-V Selects verbose mode, which will send progress reports
to stderr [Default runs "silently"].
-W Draw contour lines on top of surface or mesh (not
image). Append pen attributes used for the contours.
[Default: width = 3, color = 0/0/0, texture = solid].
-X -Y
Shift origin of plot by (x-shift,y-shift) inch
[Default is (1,1) for new plots, (0,0) for overlays].
-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 draw-
ing the contours given in the color palette file hawaii.cpt
on a Lambert map at 0.5 inch/degree along the standard
parallels 18 and 24, with vertical scale 50 mgal/inch, and
looking at the surface from SW at 30 degree elevation, try
grdview hawaii_grav.grd -Jl18/24/0.5 -Chawaii.cpt -JzLEN_3 -
Qm -N-100 -E225/30 -W > hawaii_grav_image.ps
To create a illuminated color perspective plot of the grid-
ded data set image.grd, using the color palette file
color.rgb, with linear scaling at 10 inch/x-unit and tick-
marks every 5 units, with intensities provided by the file
intens.grd, and looking from the SE, try
grdview image.grd - Jx10.0 - Ccolor.rgb - Qs - E135/30 -
Iintens.grd > image3D.ps
To make the same plot using the rastering option with dpi =
50, try
grdview image.grd -Jx10.0 - Ccolor.rgb - Qi50 - E135/30 -
Iintens.grd > image3D.ps
To create a color PostScript perspective plot of the gridded
data set magnetics.grd, using the color palette file
mag_intens.cpt, draped over the relief given by the file
topography.grd, with Mercator scaling at 1 inch/degree and
tickmarks every 1 degree, with intensities provided by the
file topo_intens.grd, and looking from the SE, try
grdview topography.grd -Jm1 -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 surface
or nearneighbor. Unfortunately, this produces huge
PostScript files. The alternative is to use the -Qi option,
which computes quasi-bilinear continuous color variations
within polygons by using scanline conversion to image the
polygons. However, when using -Qi, the -B option is deac-
tivated; plot axes separately as a psbasemap overlay.
Header must be plotted separately using pstext.
SEE ALSO
gmt, grdcontour, grdimage, nearneighbor, psbasemap, pscon-
tour, pstext, surface
REFERENCES
Wessel, P., and W. H. F. Smith, 1995, The Generic Mapping
Tools (GMT) version 3.0 Technical Reference & Cookbook,
SOEST/NOAA.
Wessel, P., and W. H. F. Smith, 1995, New Version of the
Generic Mapping Tools Released, EOS Trans. AGU, 76, p. 329.
Wessel, P., and W. H. F. Smith, 1995, New Version of the
Generic Mapping Tools Released,
http://www.agu.org/eos_elec/95154e.html, Copyright 1995 by
the American Geophysical Union.
Wessel, P., and W. H. F. Smith, 1991, Free Software Helps
Map and Display Data, EOS Trans. AGU, 72, p. 441.