grdview - Create 3-D perspective grayshaded/colored image or mesh from a 2-D grd
file
grdview relief_file -Jparameters [
-Btickinfo ] [
-Ccptfile] [
-Eview_az/view_el ] [
-Gdrapefile] [
-Iintensfile] [
-K ] [
-L[
flags] ] [
-N level[/
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
]
grdview reads a 2-D gridded file and produces a 3-D perspective 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 UNIT/degree, 1:xxxxx,
or width in UNIT (upper case modifier). UNIT is cm, inch, or m, depending
on the MEASURE_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 origin)
-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 Equator as y =
0)
-Jtlon0/lat0/scale (TM - Transverse Mercator, set origin)
-Juzone/scale (UTM - Universal Transverse Mercator)
-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 manpages.
- -Jz
- Sets the vertical scaling (for 3-D maps). Same syntax as
-Jx.
No space between the option flag and the associated arguments.
- -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[B
r/g/b]].
- -E
- Sets the view point by specifying azimuth and elevation in
degrees. [Default is 180/90]
- -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 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].
- -L
- Boundary condition flags may be x or y
or xy indicating data is periodic in range of x or y or both, or
flags may be g indicating geographical conditions (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.
- -bo
- Selects binary output. Append s for single precision
[Default is double].
- -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 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 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]
- -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 categorical data where interpolating between values is
meaningless.
- -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. Optionally, append a label, or c (which
will plot the command string.). The GMT parameters UNIX_TIME and
UNIX_TIME_POS can affect the appearance; 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 contours. [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 meshlines 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]
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
-Jl18/24/1.5
c -Chawaii.cpt
-Jz0.05
c -Qm -N-100
-E225/30
-Wc >
hawaii_grav_image.ps
To create a illuminated color perspective plot of the gridded data set
image.grd, using the color palette file color.rgb, with linear scaling at 10
cm/x-unit and tickmarks every 5 units, with intensities provided by the file
intens.grd, and looking from the SE, try
grdview image.grd
-Jx10.0
c -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
c -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 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
-JM6
i -Gmagnetics.grd
-Cmag_intens.cpt
-Qs -E140/30
-Itopo_intens.grd >
draped3D.ps
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 bilinear or bicubic continuous color variations within polygons
by using scanline conversion to image the polygons.
gmt(1gmt),
grdcontour(1gmt),
grdimage(1gmt),
nearneighbor(1gmt),
psbasemap(1gmt),
pscontour(1gmt),
pstext(1gmt),
surface(1gmt)