Geology

Modules of interest

• ps.map for cartography
• v.vol.rst for 3D raster voxel interpolation
• raster3dintro: Introduction to 3D raster processing

see also r3.* commands

• nviz: Native 3D visualization and animation suite (interactive cutting planes through stacked 3D grid surfaces, etc.)
• v.out.vtk, r.out.vtk, and r3.out.vtk: Export to VTK format for ParaView or other 3D visualization software

• d.frontline Shell script that draws frontlines on the graphics monitor using d.graph module and different types of symbols. Also it optionally saves frontline graphics to d.graph commands file and/or ps.map file (for later use with the "read" ps.map instruction).

Cartography

Examples

• See the Cartography screenshots page

Strike-and-dip symbols

See the IconSymbols wiki page

• geology/strike_line,box,triangle,circle:

• geology/strike_half-bowtie:

(to get a full bowtie: overlay two, rotate one of them by 180 degrees)

• geology/half_arrow:

(two displayed, one of which has been rotated 180 degrees)

• ps.map can take rotation angle from an attribute column for each site with the vpoints rotatecolumn instruction; for d.graph you can prepare a command file with a custom rotation for each point using v.out.ascii, v.db.select, or the v.out.ascii.db addon script. Note that GRASS uses the Cartesian convention for rotation angles, i.e. CCW from east. Convert from compass angles (CW from north) with:

    theta = 90 - degrees_true

You could possibly write a small db.execute script to populate a new column with this conversion by way of a SQL query. (and post it here :)

• to make open symbols set the fill color to 'none'.
• to make a double sided dip symbol draw the same symbol twice with 180 rotation the second time.

Fill patterns

• AreaFillPatterns: ps.map allows custom fill patterns based on simple PostScript-like rules files. A number of patterns are provided. It is reasonably simple to create new ones- just copy an existing one to a new file and edit the drawing coordinates in a text editor. (new contributions welcome)

Dashed lines

In ps.map use the vlines style instruction to set the line style. The linecap instruction can further refine the draw mode.

See also

• GRASS GSoC 2013 An Implementation of Horizon Based Stratigraphy for GRASS‎
• The Geophysics Applications page

Links

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