GRDVIEW

Section: Misc. Reference Manual Pages (l)
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#ifdef SI #define UNIT cm #define LEN_1   1.5
#define LEN_2   20
#define LEN_3   0.05
#define LEN_4   2.5
#define SCALE -Jm2.5 #else #define UNIT inch #define LEN_1   0.5
#define LEN_2   50
#define LEN_3   0.02
#define LEN_4   1
#define SCALE -Jm1 #endif  

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 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). #include "explain_-j.txt" #include "explain_-Jz.txt"
 

OPTIONS

No space between the option flag and the associated arguments. #include "explain_-b.txt"
-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 elevation 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 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]. #include "explain_-K.txt"
-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. #include "explain_-O.txt" #include "explain_-P.txt" #include "explain_-R.txt" 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]. This option will apply a simple clippath to avoid overwriting the background (since the resulting image is rectangular). Depending on the projection 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] #include "explain_-U.txt" #include "explain_-V.txt"
-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]. #include "explain_-XY.txt"
-Z
Sets the z-level of the basemap [0]. #include "explain_-c.txt"
 

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 LEN_1 UNIT/degree along the standard parallels 18 and 24, with vertical scale LEN_2 mgal/UNIT, and looking at the surface from SW at 30 degree elevation, try

grdview hawaii_grav.grd -Jl18/24/LEN_1 -Chawaii.cpt -JzLEN_3 -Qm -N-100 -E225/30 -W > 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 UNIT/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 -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 LEN_4 UNIT/degree and tickmarks every 1 degree, with intensities provided by the file topo_intens.grd, and looking from the SE, try

grdview topography.grd SCALE -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 deactivated; plot axes separately as a psbasemap overlay.

Header must be plotted separately using pstext.  

SEE ALSO

gmt, grdcontour, grdimage, nearneighbor, psbasemap, pscontour, pstext, surface #include "refs.i"


 

Index

NAME
SYNOPSIS
DESCRIPTION
OPTIONS
EXAMPLES
BUGS
SEE ALSO

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Time: 07:11:17 GMT, January 07, 2025