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 -Eview_az/view_el ] [ -Gdrapefile | -Ggrd_r,grd_g,grd_b ] [ -Iintens‐
12 file] [ -Jz|Zparameters ] [ -K ] [ -L[flags] ] [ -Nlevel[/color]] [ -O
13 ] [ -P ] [ -Qtype[g] ] [ -Rwest/east/south/north[/zmin/zmax][r] ] [
14 -Ssmooth ] [ -T[s][o[pen]] ] [ -U[just/dx/dy/][c|label] ] [ -V ] [
15 -Wtype/pen ] [ -X[a|c|r][x-shift[u]] ] [ -Y[a|c|r][y-shift[u]] ] [
16 -Zzlevel ] [ -ccopies ]
17
19 grdview reads a 2-D gridded 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 AZIMUTHAL PROJECTIONS:
66 -Jalon0/lat0[/horizon]/scale (Lambert Azimuthal Equal-Area)
68 -Jelon0/lat0[/horizon]/scale (Azimuthal Equidistant)
69 -Jflon0/lat0[/horizon]/scale (Gnomonic)
70 -Jglon0/lat0[/horizon]/scale (Orthographic)
71 -Jglon0/lat0/altitude/azimuth/tilt/twist/Width/Height/scale
72 (General Perspective).
73 -Jslon0/lat0[/horizon][/slat]/scale (General Stereographic)
74 MISCELLANEOUS PROJECTIONS:
76 -Jh[lon0/]scale (Hammer)
78 -Ji[lon0/]scale (Sinusoidal)
79 -Jkf[lon0/]scale (Eckert IV)
80 -Jk[s][lon0/]scale (Eckert IV)
81 -Jn[lon0/]scale (Robinson)
82 -Jr[lon0/]scale (Winkel Tripel)
83 -Jv[lon0/]scale (Van der Grinten)
84 -Jw[lon0/]scale (Mollweide)
85 NON-GEOGRAPHICAL PROJECTIONS:
87 -Jp[a]scale[/origin][r|z] (Polar coordinates (theta,r))
89 -Jxx-scale[d|l|ppow|t|T][/y-scale[d|l|ppow|t|T]] (Linear, log,
90 and power scaling)
91 -Jz Sets the vertical scaling (for 3-D maps). Same syntax as -Jx.
93
95 No space between the option flag and the associated arguments.
96 -B Sets map boundary annotation and tickmark intervals; see the
98 psbasemap man page for all the details.
99 -C name of the color palette file. Must be present if you want (1)
101 mesh plot with contours (-Qm), or (2) shaded/colored perspective
102 image (-Qs or -Qi). For -Qs: You can specify that you want to
103 skip a z-slice by setting red = -; to use a pattern give red =
104 P|pdpi/pattern[:Fr/g/b[Br/g/b]].
105 -E Sets the view point by specifying azimuth and elevation in
107 degrees. [Default is 180/90].
108 -G Drape the image in drapefile on top of the relief provided by
110 relief_file. [Default is relief_file]. Note that -Jz and -N
111 always refers to the relief_file. The drapefile only provides
112 the information pertaining to colors, which is looked-up via the
113 cpt file (see -C). Alternatively, give three grid files sepa‐
114 rated by commas. These files must contain the red, green, and
115 blue colors directly (in 0-255 range) and no cpt file is needed.
116 The drapefile may be of higher resolution than the relief_file.
117 -I Gives the name of a grid file with intensities in the (-1,+1)
119 range. [Default is no illumination].
120 -K More PostScript code will be appended later [Default terminates
122 the plot system].
123 -L Boundary condition flags may be x or y or xy indicating data is
125 periodic in range of x or y or both, or flags may be g indicat‐
126 ing geographical conditions (x and y are lon and lat). [Default
127 uses "natural" conditions (second partial derivative normal to
128 edge is zero).] If no flags are set, use bilinear rather than
129 the default bicubic resampling when draping is required.
130 -N Draws a plane at this z-level. If the optional color is pro‐
132 vided, the frontal facade between the plane and the data perime‐
133 ter is colored. See -Wf for setting the pen used for the out‐
134 line. (See SPECIFYING COLOR below).
135 -O Selects Overlay plot mode [Default initializes a new plot sys‐
137 tem].
138 -P Selects Portrait plotting mode [Default is Landscape, see gmtde‐
140 faults to change this].
141 -Q Select one of four settings: 1. Specify m for mesh plot
143 [Default], and optionally append /color for a different mesh
144 paint [white]. 2. Specify s for surface plot, and optionally
145 append m to have mesh lines drawn on top of surface. 3. Specify
146 i for image plot, and optionally append the effective dpi reso‐
147 lution for the rasterization [100]. 4. Specify c. Same as -Qi
148 but will make nodes with z = NaN transparent, using the color‐
149 masking feature in PostScript Level 3 (the PS device must sup‐
150 port PS Level 3). For any of these choices, you may force a
151 monochrome image by appending g. Colors are then converted to
152 shades of gray using the (television) YIQ transformation.
153 -R xmin, xmax, ymin, and ymax specify the Region of interest. For
155 geographic regions, these limits correspond to west, east,
156 south, and north and you may specify them in decimal degrees or
157 in [+-]dd:mm[:ss.xxx][W|E|S|N] format. Append r if lower left
158 and upper right map coordinates are given instead of w/e/s/n.
159 The two shorthands -Rg and -Rd stand for global domain (0/360
160 and -180/+180 in longitude respectively, with -90/+90 in lati‐
161 tude). For calendar time coordinates you may either give (a)
162 relative time (relative to the selected TIME_EPOCH and in the
163 selected TIME_UNIT; append t to -JX|x), or (b) absolute time of
164 the form [date]T[clock] (append T to -JX|x). At least one of
165 date and clock must be present; the T is always required. The
166 date string must be of the form [-]yyyy[-mm[-dd]] (Gregorian
167 calendar) or yyyy[-Www[-d]] (ISO week calendar), while the clock
168 string must be of the form hh:mm:ss[.xxx]. The use of delim‐
169 iters and their type and positions must be exactly as indicated
170 (however, input, output and plot formats are customizable; see
171 gmtdefaults). This option may be used to indicate the range
172 used for the 3-D axes [Default is region given by the
173 relief_file]. You may ask for a larger w/e/s/n region to have
174 more room between the image and the axes. A smaller region than
175 specified in the relief_file will result in a subset of the
176 grid.
177 -S Smooth the contours before plotting (see grdcontour) [Default is
179 no smoothing].
180 -T Plot image without any interpolation. This involves converting
182 each node-centered bin into a polygon which is then painted sep‐
183 arately. Append s to skip nodes with z = NaN. This option is
184 useful for categorical data where interpolating between values
185 is meaningless. Optionally, append o to draw the tile outlines,
186 and specify a custom pen if the default pen is not to your lik‐
187 ing. As this option produces a flat surface it cannot be com‐
188 bined with -JZ or -Jz. (See SPECIFYING PENS below).
189 -U Draw Unix System time stamp on plot. By adding just/dx/dy/, the
191 user may specify the justification of the stamp and where the
192 stamp should fall on the page relative to lower left corner of
193 the plot. For example, BL/0/0 will align the lower left corner
194 of the time stamp with the lower left corner of the plot.
195 Optionally, append a label, or c (which will plot the command
196 string.). The GMT parameters UNIX_TIME, UNIX_TIME_POS, and
197 UNIX_TIME_FORMAT can affect the appearance; see the gmtdefaults
198 man page for details. The time string will be in the locale set
199 by the environment variable TZ (generally local time).
200 -V Selects verbose mode, which will send progress reports to stderr
202 [Default runs "silently"].
203 -Wc Draw contour lines on top of surface or mesh (not image).
205 Append pen attributes used for the contours. [Default: width =
206 3, color = black, texture = solid]. (See SPECIFYING PENS
207 below).
208 -Wm Sets the pen attributes used for the mesh. [Default: width = 1,
210 color = black, texture = solid]. You must also select -Qm or
211 -Qsm for meshlines to be drawn.
212 -Wf Sets the pen attributes used for the facade. [Default: width =
214 1, color = black, texture = solid]. You must also select -N for
215 the facade outline to be drawn. (See SPECIFYING PENS below).
216 -X -Y Shift plot origin relative to the current origin by (x-shift,y-
218 shift) and optionally append the length unit (c, i, m, p). You
219 can prepend a to shift the origin back to the original position
220 after plotting, or prepend r [Default] to reset the current
221 origin to the new location. If -O is used then the default (x-
222 shift,y-shift) is (0,0), otherwise it is (r1i, r1i) or (r2.5c,
223 r2.5c). Alternatively, give c to align the center coordinate (x
224 or y) of the plot with the center of the page based on current
225 page size.
226 -Z Sets the z-level of the basemap [0].
228 -c Specifies the number of plot copies. [Default is 1].
230 SPECIFYING PENS
232 pen The attributes of lines and symbol outlines as defined by pen is
233 a comma delimetered list of width, color and texture, each of
234 which is optional. width can be indicated as a measure (points,
235 centimeters, inches) or as faint, thin[ner|nest], thick[er|est],
236 fat[ter|test], or obese. color specifies a grey shade or color
237 (see SPECIFYING COLOR below). texture is a combination of
238 dashes `-' and dots `.'.
239 SPECIFYING COLOR
241 color The color of lines, areas and patterns can be specified by a
242 valid color name; by a grey shade (in the range 0-255); by a
243 decimal color code (r/g/b, each in range 0-255; h-s-v, ranges
244 0-360, 0-1, 0-1; or c/m/y/k, each in range 0-1); or by a hexa‐
245 decimal color code (#rrggbb, as used in HTML). See the gmtcol‐
246 ors manpage for more information and a full list of color names.
247
249 GMT is able to recognize many of the commonly used grid file formats,
250 as well as the precision, scale and offset of the values contained in
251 the grid file. When GMT needs a little help with that, you can add the
252 suffix =id[/scale/offset[/nan]], where id is a two-letter identifier of
253 the grid type and precision, and scale and offset are optional scale
254 factor and offset to be applied to all grid values, and nan is the
255 value used to indicate missing data. See grdreformat(1) and Section
256 4.17 of the GMT Technical Reference and Cookbook for more information.
257 When reading a netCDF file that contains multiple grids, GMT will read,
259 by default, the first 2-dimensional grid that can find in that file. To
260 coax GMT into reading another multi-dimensional variable in the grid
261 file, append ?varname to the file name, where varname is the name of
262 the variable. Note that you may need to escape the special meaning of ?
263 in your shell program by putting a backslash in front of it, or by
264 placing the filename and suffix between quotes or double quotes. See
265 grdreformat(1) and Section 4.18 of the GMT Technical Reference and
266 Cookbook for more information, particularly on how to read splices of
267 3-, 4-, or 5-dimensional grids.
268
270 To make a mesh plot from the file hawaii_grav.grd and drawing the con‐
271 tours given in the color palette file hawaii.cpt on a Lambert map at
272 1.5 cm/degree along the standard parallels 18 and 24, with vertical
273 scale 20 mgal/cm, and looking at the surface from SW at 30 degree ele‐
274 vation, run
275 grdview hawaii_grav.grd -Jl18/24/1.5c -Chawaii.cpt -Jz0.05c -Qm -N-100
277 -E225/30 -Wc > hawaii_grav_image.ps
278 To create a illuminated color perspective plot of the gridded data set
280 image.grd, using the color palette file color.rgb, with linear scaling
281 at 10 cm/x-unit and tickmarks every 5 units, with intensities provided
282 by the file intens.grd, and looking from the SE, use
283 grdview image.grd -Jx10.0c -Ccolor.rgb -Qs -E135/30 -Iintens.grd >
285 image3D.ps
286 To make the same plot using the rastering option with dpi = 50, use
288 grdview image.grd -Jx10.0c -Ccolor.rgb -Qi50 -E135/30 -Iintens.grd >
290 image3D.ps
291 To create a color PostScript perspective plot of the gridded data set
293 magnetics.grd, using the color palette file mag_intens.cpt, draped over
294 the relief given by the file topography.grd, with Mercator map width of
295 6 inch and tickmarks every 1 degree, with intensities provided by the
296 file topo_intens.grd, and looking from the SE, run
297 grdview topography.grd -JM6i -Gmagnetics.grd -Cmag_intens.cpt -Qs
299 -E140/30 -Itopo_intens.grd > draped3D.ps
300 Given topo.grd and the Landsat image veggies.ras, first run gmt2rgb to
302 get the red, green, and blue grids, and then drape this image over the
303 topography and shade the result for good measure. The commands are
304 gmt2rgb veggies.ras -Glayer_%c.grd
306 grdview topo.grd -JM6i -Qi -E140/30 -Itopo_intens.grd
307 -Glayer_r.grd,layer_g.grd,layer_b.grd > image.ps
308
310 For the -Qs option: PostScript provides no way of smoothly varying
311 colors within a polygon, so colors can only vary from polygon to poly‐
312 gon. To obtain smooth images this way you may resample the grid
313 file(s) using grdsample or use a finer grid size when running gridding
314 programs like surface or nearneighbor. Unfortunately, this produces
315 huge PostScript files. The alternative is to use the -Qi option, which
316 computes bilinear or bicubic continuous color variations within poly‐
317 gons by using scanline conversion to image the polygons.
318
320 GMT(1), gmt2rgb(1), grdcontour(1), grdimage(1), nearneighbor(1),
321 psbasemap(1), pscontour(1), pstext(1), surface(1)
322GMT 4.3.1 15 May 2008 GRDVIEW(1)