1GRDVIEW(1) Generic Mapping Tools GRDVIEW(1)
2
6 grdview - Create 3-D perspective grayshaded/colored image or mesh from
7 a 2-D grid file
8
10 grdview relief_file -Jparameters [ -B[p|s]parameters ] [ -Ccptfile ] [
11 -Eazim/elev[+wlon/lat[/z]][+vx0/y0] ] [ -Gdrapefile |
12 -Ggrd_r,grd_g,grd_b ] [ -Iintensfile ] [ -Jz|Zparameters ] [ -K ] [
13 -L[flags] ] [ -Nlevel[/color] ] [ -O ] [ -P ] [ -Qtype[g] ] [
14 -Rwest/east/south/north[/zmin/zmax][r] ] [ -Ssmooth ] [ -T[s][o[pen]] ]
15 [ -U[just/dx/dy/][c|label] ] [ -V ] [ -Wtype/pen ] [ -X[a|c|r][x-
16 shift[u]] ] [ -Y[a|c|r][y-shift[u]] ] [ -Zzlevel ] [ -ccopies ]
17
19 grdview reads a 2-D grid file and produces a 3-D perspective plot by
20 drawing a mesh, painting a colored/grayshaded surface made up of poly‐
21 gons, or by scanline conversion of these polygons to a rasterimage.
22 Options include draping a data set on top of a surface, plotting of
23 contours on top of the surface, and apply artificial illumination based
24 on intensities provided in a separate grid file.
25 relief_file
27 2-D gridded data set to be imaged (the relief of the surface).
28 (See GRID FILE FORMAT below.)
29 -J Selects the map projection. Scale is UNIT/degree, 1:xxxxx, or
31 width in UNIT (upper case modifier). UNIT is cm, inch, or m,
32 depending on the MEASURE_UNIT setting in .gmtdefaults4, but this
33 can be overridden on the command line by appending c, i, or m to
34 the scale/width value. When central meridian is optional,
35 default is center of longitude range on -R option. Default
36 standard parallel is the equator. For map height, max dimen‐
37 sion, or min dimension, append h, +, or - to the width, respec‐
38 tively.
39 More details can be found in the psbasemap man pages.
40 CYLINDRICAL PROJECTIONS:
42 -Jclon0/lat0/scale (Cassini)
44 -Jcyl_stere/[lon0/[lat0/]]scale (Cylindrical Stereographic)
45 -Jj[lon0/]scale (Miller)
46 -Jm[lon0/[lat0/]]scale (Mercator)
47 -Jmlon0/lat0/scale (Mercator - Give meridian and standard paral‐
48 lel)
49 -Jo[a]lon0/lat0/azimuth/scale (Oblique Mercator - point and
50 azimuth)
51 -Jo[b]lon0/lat0/lon1/lat1/scale (Oblique Mercator - two points)
52 -Joclon0/lat0/lonp/latp/scale (Oblique Mercator - point and
53 pole)
54 -Jq[lon0/[lat0/]]scale (Cylindrical Equidistant)
55 -Jtlon0/[lat0/]scale (TM - Transverse Mercator)
56 -Juzone/scale (UTM - Universal Transverse Mercator)
57 -Jy[lon0/[lat0/]]scale (Cylindrical Equal-Area)
58 CONIC PROJECTIONS:
60 -Jblon0/lat0/lat1/lat2/scale (Albers)
62 -Jdlon0/lat0/lat1/lat2/scale (Conic Equidistant)
63 -Jllon0/lat0/lat1/lat2/scale (Lambert Conic Conformal)
64 -Jpoly/[lon0/[lat0/]]scale ((American) Polyconic)
65 AZIMUTHAL PROJECTIONS:
67 -Jalon0/lat0[/horizon]/scale (Lambert Azimuthal Equal-Area)
69 -Jelon0/lat0[/horizon]/scale (Azimuthal Equidistant)
70 -Jflon0/lat0[/horizon]/scale (Gnomonic)
71 -Jglon0/lat0[/horizon]/scale (Orthographic)
72 -Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale
73 (General Perspective).
74 -Jslon0/lat0[/horizon]/scale (General Stereographic)
75 MISCELLANEOUS PROJECTIONS:
77 -Jh[lon0/]scale (Hammer)
79 -Ji[lon0/]scale (Sinusoidal)
80 -Jkf[lon0/]scale (Eckert IV)
81 -Jk[s][lon0/]scale (Eckert VI)
82 -Jn[lon0/]scale (Robinson)
83 -Jr[lon0/]scale (Winkel Tripel)
84 -Jv[lon0/]scale (Van der Grinten)
85 -Jw[lon0/]scale (Mollweide)
86 NON-GEOGRAPHICAL PROJECTIONS:
88 -Jp[a]scale[/origin][r|z] (Polar coordinates (theta,r))
90 -Jxx-scale[d|l|ppow|t|T][/y-scale[d|l|ppow|t|T]] (Linear, log,
91 and power scaling)
92 -Jz Sets the vertical scaling (for 3-D maps). Same syntax as -Jx.
94
96 No space between the option flag and the associated arguments.
97 -B Sets map boundary annotation and tickmark intervals; see the
99 psbasemap man page for all the details.
100 -C name of the color palette file. Must be present if you want (1)
102 mesh plot with contours (-Qm), or (2) shaded/colored perspective
103 image (-Qs or -Qi). For -Qs: You can specify that you want to
104 skip a z-slice by setting red = -; to use a pattern give red =
105 P|pdpi/pattern[:Fr/g/b[Br/g/b]].
106 -E Sets the viewpoint's azimuth and elevation (for perspective
108 view) [180/90]. For frames used for animation, you may want to
109 append + to fix the center of your data domain (or specify a
110 particular world coordinate point with +wlon0/lat[/z]) which
111 will project to the center of your page size (or specify the
112 coordinates of the projected veiw point with +vx0/y0).
113 -G Drape the image in drapefile on top of the relief provided by
115 relief_file. [Default is relief_file]. Note that -Jz and -N
116 always refers to the relief_file. The drapefile only provides
117 the information pertaining to colors, which is looked-up via the
118 cpt file (see -C). Alternatively, give three grid files sepa‐
119 rated by commas. These files must contain the red, green, and
120 blue colors directly (in 0-255 range) and no cpt file is needed.
121 The drapefile may be of higher resolution than the relief_file.
122 -I Gives the name of a grid file with intensities in the (-1,+1)
124 range. [Default is no illumination].
125 -K More PostScript code will be appended later [Default terminates
127 the plot system].
128 -L Boundary condition flags may be x or y or xy indicating data is
130 periodic in range of x or y or both, or flags may be g indicat‐
131 ing geographical conditions (x and y are lon and lat). [Default
132 uses "natural" conditions (second partial derivative normal to
133 edge is zero).] If no flags are set, use bilinear rather than
134 the default bicubic resampling when draping is required.
135 -N Draws a plane at this z-level. If the optional color is pro‐
137 vided, the frontal facade between the plane and the data perime‐
138 ter is colored. See -Wf for setting the pen used for the out‐
139 line. (See SPECIFYING COLOR below).
140 -O Selects Overlay plot mode [Default initializes a new plot sys‐
142 tem].
143 -P Selects Portrait plotting mode [Default is Landscape, see gmtde‐
145 faults to change this].
146 -Q Select one of four settings: 1. Specify m for mesh plot
148 [Default], and optionally append /color for a different mesh
149 paint [white]. 2. Specify s for surface plot, and optionally
150 append m to have mesh lines drawn on top of surface. 3. Specify
151 i for image plot, and optionally append the effective dpi reso‐
152 lution for the rasterization [100]. 4. Specify c. Same as -Qi
153 but will make nodes with z = NaN transparent, using the color‐
154 masking feature in PostScript Level 3 (the PS device must sup‐
155 port PS Level 3). For any of these choices, you may force a
156 monochrome image by appending g. Colors are then converted to
157 shades of gray using the (television) YIQ transformation.
158 -R xmin, xmax, ymin, and ymax specify the Region of interest. For
160 geographic regions, these limits correspond to west, east,
161 south, and north and you may specify them in decimal degrees or
162 in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left
163 and upper right map coordinates are given instead of w/e/s/n.
164 The two shorthands -Rg and -Rd stand for global domain (0/360
165 and -180/+180 in longitude respectively, with -90/+90 in lati‐
166 tude). Alternatively, specify the name of an existing grid file
167 and the -R settings (and grid spacing, if applicable) are copied
168 from the grid. For calendar time coordinates you may either
169 give (a) relative time (relative to the selected TIME_EPOCH and
170 in the selected TIME_UNIT; append t to -JX|x), or (b) absolute
171 time of the form [date]T[clock] (append T to -JX|x). At least
172 one of date and clock must be present; the T is always required.
173 The date string must be of the form [-]yyyy[-mm[-dd]] (Gregorian
174 calendar) or yyyy[-Www[-d]] (ISO week calendar), while the clock
175 string must be of the form hh:mm:ss[.xxx]. The use of delim‐
176 iters and their type and positions must be exactly as indicated
177 (however, input, output and plot formats are customizable; see
178 gmtdefaults). This option may be used to indicate the range
179 used for the 3-D axes [Default is region given by the
180 relief_file]. You may ask for a larger w/e/s/n region to have
181 more room between the image and the axes. A smaller region than
182 specified in the relief_file will result in a subset of the
183 grid.
184 -S Smooth the contours before plotting (see grdcontour) [Default is
186 no smoothing].
187 -T Plot image without any interpolation. This involves converting
189 each node-centered bin into a polygon which is then painted sep‐
190 arately. Append s to skip nodes with z = NaN. This option is
191 useful for categorical data where interpolating between values
192 is meaningless. Optionally, append o to draw the tile outlines,
193 and specify a custom pen if the default pen is not to your lik‐
194 ing. As this option produces a flat surface it cannot be com‐
195 bined with -JZ or -Jz. (See SPECIFYING PENS below).
196 -U Draw Unix System time stamp on plot. By adding just/dx/dy/, the
198 user may specify the justification of the stamp and where the
199 stamp should fall on the page relative to lower left corner of
200 the plot. For example, BL/0/0 will align the lower left corner
201 of the time stamp with the lower left corner of the plot.
202 Optionally, append a label, or c (which will plot the command
203 string.). The GMT parameters UNIX_TIME, UNIX_TIME_POS, and
204 UNIX_TIME_FORMAT can affect the appearance; see the gmtdefaults
205 man page for details. The time string will be in the locale set
206 by the environment variable TZ (generally local time).
207 -V Selects verbose mode, which will send progress reports to stderr
209 [Default runs "silently"].
210 -Wc Draw contour lines on top of surface or mesh (not image).
212 Append pen attributes used for the contours. [Default: width =
213 0.75p, color = black, texture = solid]. (See SPECIFYING PENS
214 below).
215 -Wm Sets the pen attributes used for the mesh. [Default: width =
217 0.25p, color = black, texture = solid]. You must also select
218 -Qm or -Qsm for meshlines to be drawn.
219 -Wf Sets the pen attributes used for the facade. [Default: width =
221 0.25p, color = black, texture = solid]. You must also select -N
222 for the facade outline to be drawn. (See SPECIFYING PENS
223 below).
224 -X -Y Shift plot origin relative to the current origin by (x-shift,y-
226 shift) and optionally append the length unit (c, i, m, p). You
227 can prepend a to shift the origin back to the original position
228 after plotting, or prepend r [Default] to reset the current
229 origin to the new location. If -O is used then the default (x-
230 shift,y-shift) is (0,0), otherwise it is (r1i, r1i) or (r2.5c,
231 r2.5c). Alternatively, give c to align the center coordinate (x
232 or y) of the plot with the center of the page based on current
233 page size.
234 -Z Sets the z-level of the basemap [0].
236 -c Specifies the number of plot copies. [Default is 1].
238 SPECIFYING PENS
240 pen The attributes of lines and symbol outlines as defined by pen is
241 a comma delimetered list of width, color and texture, each of
242 which is optional. width can be indicated as a measure (points,
243 centimeters, inches) or as faint, thin[ner|nest], thick[er|est],
244 fat[ter|test], or obese. color specifies a gray shade or color
245 (see SPECIFYING COLOR below). texture is a combination of
246 dashes `-' and dots `.'.
247 SPECIFYING COLOR
249 color The color of lines, areas and patterns can be specified by a
250 valid color name; by a gray shade (in the range 0-255); by a
251 decimal color code (r/g/b, each in range 0-255; h-s-v, ranges
252 0-360, 0-1, 0-1; or c/m/y/k, each in range 0-1); or by a hexa‐
253 decimal color code (#rrggbb, as used in HTML). See the gmtcol‐
254 ors manpage for more information and a full list of color names.
255
257 GMT is able to recognize many of the commonly used grid file formats,
258 as well as the precision, scale and offset of the values contained in
259 the grid file. When GMT needs a little help with that, you can add the
260 suffix =id[/scale/offset[/nan]], where id is a two-letter identifier of
261 the grid type and precision, and scale and offset are optional scale
262 factor and offset to be applied to all grid values, and nan is the
263 value used to indicate missing data. See grdreformat(1) and Section
264 4.17 of the GMT Technical Reference and Cookbook for more information.
265 When reading a netCDF file that contains multiple grids, GMT will read,
267 by default, the first 2-dimensional grid that can find in that file. To
268 coax GMT into reading another multi-dimensional variable in the grid
269 file, append ?varname to the file name, where varname is the name of
270 the variable. Note that you may need to escape the special meaning of ?
271 in your shell program by putting a backslash in front of it, or by
272 placing the filename and suffix between quotes or double quotes. See
273 grdreformat(1) and Section 4.18 of the GMT Technical Reference and
274 Cookbook for more information, particularly on how to read splices of
275 3-, 4-, or 5-dimensional grids.
276
278 To make a mesh plot from the file hawaii_grav.grd and drawing the con‐
279 tours given in the color palette file hawaii.cpt on a Lambert map at
280 1.5 cm/degree along the standard parallels 18 and 24, with vertical
281 scale 20 mgal/cm, and looking at the surface from SW at 30 degree ele‐
282 vation, run
283 grdview hawaii_grav.grd -Jl18/24/1.5c -Chawaii.cpt -Jz0.05c -Qm -N-100
285 -E225/30 -Wc > hawaii_grav_image.ps
286 To create a illuminated color perspective plot of the gridded data set
288 image.grd, using the color palette file color.rgb, with linear scaling
289 at 10 cm/x-unit and tickmarks every 5 units, with intensities provided
290 by the file intens.grd, and looking from the SE, use
291 grdview image.grd -Jx10.0c -Ccolor.rgb -Qs -E135/30 -Iintens.grd >
293 image3D.ps
294 To make the same plot using the rastering option with dpi = 50, use
296 grdview image.grd -Jx10.0c -Ccolor.rgb -Qi50 -E135/30 -Iintens.grd >
298 image3D.ps
299 To create a color PostScript perspective plot of the gridded data set
301 magnetics.grd, using the color palette file mag_intens.cpt, draped over
302 the relief given by the file topography.grd, with Mercator map width of
303 6 inch and tickmarks every 1 degree, with intensities provided by the
304 file topo_intens.grd, and looking from the SE, run
305 grdview topography.grd -JM6i -Gmagnetics.grd -Cmag_intens.cpt -Qs
307 -E140/30 -Itopo_intens.grd > draped3D.ps
308 Given topo.grd and the Landsat image veggies.ras, first run gmt2rgb to
310 get the red, green, and blue grids, and then drape this image over the
311 topography and shade the result for good measure. The commands are
312 gmt2rgb veggies.ras -Glayer_%c.grd
314 grdview topo.grd -JM6i -Qi -E140/30 -Itopo_intens.grd
315 -Glayer_r.grd,layer_g.grd,layer_b.grd > image.ps
316
318 For the -Qs option: PostScript provides no way of smoothly varying
319 colors within a polygon, so colors can only vary from polygon to poly‐
320 gon. To obtain smooth images this way you may resample the grid
321 file(s) using grdsample or use a finer grid size when running gridding
322 programs like surface or nearneighbor. Unfortunately, this produces
323 huge PostScript files. The alternative is to use the -Qi option, which
324 computes bilinear or bicubic continuous color variations within poly‐
325 gons by using scanline conversion to image the polygons.
326
328 GMT(1), gmt2rgb(1), gmtcolors(5), grdcontour(1), grdimage(1),
329 nearneighbor(1), psbasemap(1), pscontour(1), pstext(1), surface(1)
330GMT 4.5.6 10 Mar 2011 GRDVIEW(1)