NAME¶
grdview - Create 3-D perspective grayshaded/colored image or mesh from a 2-D grd
file
SYNOPSIS¶
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
]
DESCRIPTION¶
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.
OPTIONS¶
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|p
dpi/pattern[:Fr/g/b[Br/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]
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
-Jl18/24/1.5
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
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 bilinear or bicubic continuous color variations within polygons
by using scanline conversion to image the polygons.
SEE ALSO¶
gmt(1gmt),
grdcontour(1gmt),
grdimage(1gmt),
nearneighbor(1gmt),
psbasemap(1gmt),
pscontour(1gmt),
pstext(1gmt),
surface(1gmt)