Common Tasks

Mini-tutorials showcasing some common GIS tasks

Import/Export and Display

• Import and display SRTM elevation data

r.in.srtm

• GRASS Newsletter, 3, June 2005.
• You can also get the SRTM data with a convenient web interface at http://srtm.csi.cgiar.org/. These come in 5 degree blocks and can be downloaded either as Geotiff or Ascii files.

• Import and display VMap0 Digital Chart of the World

v.in.ogr

• GRASS Newsletter, 3, June 2005.
• If your region crosses the boundaries of a VMap0 block you can use the v.append command, available in the Grass Addons section of this wiki, to combine vectors across the edges. It can take quite a while to complete.

• Import and display ETOPO2 world elevation and bathymetry dataset

r.in.bin

• Global dataset of bathymetry and topography. GRASS Newsletter, 1:8-11, August 2004.

General Import / Export

• Raster import and export with r.in.gdal / r.out.gdal
  • r.in.gdal misc. tips
  • r.out.gdal data types, creation options, new flags

• Vector import and export with v.in.ogr / v.out.ogr
  • v.in.ogr misc. tips, shapefile gotchas
  • v.out.ogr data types, dsn, new flags

• Map Export for GpsDrive navigation software

GIS Tasks

• Map (re-)projection
  • r.proj and v.proj (snippets from manual pages)
  • gdal_warp as an alternative for large, complex (re-)projection tasks
  • ogr2ogr as an alternative to v.proj

• Georectify a scanned raster image
  • r.in.gdal into XY location
  • gis.m GUI georectifier
  • i.points + i.rectify (alternate method)

• Trace vector contours from a scanned map

• Create a DEM from contour lines and trig points
  • r.surf.contour (see the Contour lines to DEM wiki page)

• Create a DEM from x,y,z point data
  • v.surf.rst
  • v.surf.idw
  • v.surf.bspline
  • r.surf.nnbathy (GRASS Addons)

• Create vector contour lines from a raster DEM
  • r.contour

3D Visualization

• Use NVIZ to render a 3D image

nviz elevation.dem

• Use NVIZ to make a fly through movie
  • see nviz keyframe animation panel help page
  • Encoding Movies
• GRASS and Paraview
• Use Paraview to render a 3D image
  • r.out.vtk, r3.out.vtk, v.out.vtk
  • GRASS and Paraview

Raster operations

Creation

• slope, aspect and surface parameters
  • r.slope.aspect
  • r.param.scale

• Create a shaded relief map
  • r.shaded.relief

• drape semi-transparent land use map over shaded relief map
  • d.his

Analysis

• cost surface analysis
  • r.cost
  • r.drain (fun examples)
  • r.walk (fun examples) [how output is different]

Vector operations

• Disolve interior lines
  • v.dissolve

Hardcopy and Graphics Creation

• create PostScript with ps.map (instructions in file, command line interface)
• use wxGUI Cartographic Composer (graphical user interface to ps.map, creates PDF or PostScript)
• use standard GRASS GIS Map Display (or its command line interface from Python or Bash) and finalize with Inkscape
• export to GMT (Generic Mapping Tools)
• export to QGIS and use Cartography Composer there