Modules (Classic Mode)
Note
Looking for the modern mode modules like begin and figure? See the
equivalent page for modern mode.
This is a list of all GMT “classic mode” core and supplemental modules and their uses, as well as some utility scripts. These modules are fully compatible with GMT 4 and 5. All modules are requested via a call to the gmt program.
Program
Core Modules
Supplemental Modules
Utility Scripts
Plotting
| Plot the GMT logo | |
| Make contour map using a grid | |
| Project and plot grids or images | |
| Plot vector field from two component grids | |
| Create 3-D perspective image or surface mesh from a grid | |
| Plot base maps and frames | |
| Initialize or terminate polygonal clip paths | |
| Plot continents, countries, shorelines, rivers, and borders | |
| Contour table data by direct triangulation | |
| Plot event symbols, lines, polygons and labels for one moment in time | |
| Calculate and plot histograms | |
| Plot raster or EPS images | |
| Plot a legend | |
| Clip or mask map areas with no data table coverage | |
| Plot a polar histogram (rose, sector, windrose diagrams) | |
| Plot gray scale or color scale bar | |
| Plot day-night terminators and other sunlight parameters | |
| Plot data on ternary diagrams | |
| Plot or typeset text | |
| Plot z = f(x,y) anomalies along tracks | |
| Plot lines, polygons, and symbols in 2-D | |
| Plot lines, polygons, and symbols in 3-D | 
Filtering
| Block average (x,y,z) data tables by mean estimation | |
| Block average (x,y,z) data tables by median estimation | |
| Block average (x,y,z) data tables by mode estimation | |
| Directional filtering of grids in the space domain | |
| Time domain filtering of 1-D data tables | |
| Filter a grid in the space (or time) domain | 
Gridding
| Interpolate using Green’s functions for splines in 1-3 dimensions | |
| Grid table data using a "Nearest neighbor" algorithm | |
| Spherical gridding in tension of data on a sphere | |
| Grid table data using adjustable tension continuous curvature splines | |
| Delaunay triangulation or Voronoi partitioning and gridding of Cartesian data | |
| Interpolate a 3-D cube, 2-D grids or 1-D series from a 3-D data cube or stack of 2-D grids | 
Sampling of 1-D and 2-D data
| Line reduction using the Douglas-Peucker algorithm | |
| Resample a grid onto a new lattice | |
| Sample one or more grids at specified locations | |
| Resample 1-D table data using splines | 
Projection and map-transformation
| Forward and inverse map transformation of grids | |
| Forward and inverse map transformations, datum conversions and geodesy | |
| Project data onto lines or great circles, or generate tracks | 
Information retrieval
| List current GMT default settings | |
| Get individual GMT default settings or download data sets | |
| Get information about data tables | |
| Change individual GMT default settings | |
| Extract information from 2-D grids or 3-D cubes | |
| Make selections or determine common regions from 2-D grids, images or 3-D cubes | 
Mathematical operations on tables or grids
| Reverse Polish Notation (RPN) calculator for data tables | |
| Make GMT color palette tables | |
| Compute auto- [and cross-] spectra from one [or two] time series | |
| Compute grid from spherical harmonic coefficients | |
| Create Voronoi distance, node, or natural nearest-neighbor grid on a sphere | |
| Delaunay or Voronoi construction of spherical data | 
Convert or extract subsets of data
| Bin spatial data and determine statistics per bin | |
| Connect individual lines whose end points match within tolerance | |
| Convert, paste, or extract columns from data tables | |
| Select data table subsets based on multiple spatial criteria | |
| Geospatial operations on points, lines and polygons | |
| Split xyz[dh] data tables into individual segments | |
| Operations on Cartesian vectors in 2-D and 3-D | |
| Create KML image quadtree from single grid | |
| Convert grid to data table | |
| Blend several partially overlapping grids into one larger grid | |
| Convert between different grid formats | |
| Extract subregion from a grid or image or a slice from a cube | |
| Join two grids along their common edge | |
| Convert data table to a grid | 
Trends in 1-D and 2-D data
| Find mean position and great [or small] circle fit to points on sphere | |
| Linear regression of 1-D data sets | |
| Fit trend surface to grids and compute residuals | |
| Fit [weighted] [robust] polynomial/Fourier model for y = f(x) to xy[w] data | |
| Fit [weighted] [robust] polynomial for z = f(x,y) to xyz[w] data | 
Grid operations
| Make linear or histogram-equalized color palette table from grid | |
| Clip the range of grid values | |
| Modify header or content of a grid | |
| Mathematical operations on grids in the spectral domain | |
| Interpolate across holes in a grid | |
| Compute directional gradients from a grid | |
| Perform histogram equalization for a grid | |
| Create a "wet-dry" mask grid from shoreline data base | |
| Create mask grid from polygons or point coverage | |
| Reverse Polish Notation (RPN) calculator for grids (element by element) | |
| Blending and transforming grids and images | |
| Calculate grid volume and area constrained by a contour | 
Miscellaneous
| Automate batch job processing | |
| Show HTML documentation of specified module | |
| Convert GMT data table to Google Earth KML file | |
| Execute GDAL raster programs from GMT | |
| Find full path to specified files | |
| Extract GMT table data from Google Earth KML files | |
| Convert [E]PS file(s) to other formats using Ghostscript | 
geodesy
| Compute grids or time-series of solid Earth tides | |
| Interpolate GPS velocities using Green’s functions for elastic deformation | |
| Plot velocity vectors, crosses, anisotropy bars and wedges | 
GSFML
| Analysis of fracture zones using crossing profiles | |
| Produce a smooth blended FZ trace | |
| Bash script to plot statistical information related to fracture zones | |
| Bash script to plot fracture zone cross-profiles on a Mercator map | |
| Bash script to build fracture zone cross-profile model | |
| Bash script to plot fracture zone cross-profiles | |
| Convert chrons to ages using selected magnetic timescale | 
GSHHG
| Extract data tables from binary GSHHG or WDBII data files | 
IMG
| Extract a subset from an img file in Mercator or Geographic format | 
MGD77
| Convert MGD77 data to other formats | |
| Create MGD77 headers from A77 files | |
| Extract information about MGD77 files | |
| Extract data from MGD77 files | |
| Evaluate the IGRF or CM4 magnetic field models | |
| Manage the content of MGD77+ files | |
| Return paths to MGD77 cruises and directories | |
| Along-track quality control of MGD77 cruises | |
| Plot track-lines of MGD77 cruises | 
potential
| Compute flexural deformation of 2-D loads, forces, and bending moments | |
| Compute the gravity/magnetic anomaly of a 3-D body by the method of Okabe | |
| Spectral calculations of gravity, isostasy, admittance, and coherence for grids | |
| Compute geopotential anomalies over 3-D vertical prisms | |
| Compute flexural deformation of 3-D surfaces for various rheologies | |
| Computes the gravity effect of one (or two) grids by the method of Okabe | |
| Compute the Continuous Reduction To the Pole, AKA differential RTP | |
| Create synthetic seamounts (Gaussian, parabolic, polynomial, cone or disc; circular or elliptical) | |
| Compute geopotential anomalies over 2-D bodies by the method of Talwani | |
| Compute geopotential anomalies over 3-D bodies by the method of Talwani | 
SEGY
| Plot a SEGY file in 3-D | |
| Plot a SEGY file in 2-D | |
| Converting SEGY data to a grid | 
seis
| Plot cross-sections of focal mechanisms | |
| Plot focal mechanisms | |
| Plot polarities on the lower hemisphere of the focal sphere | |
| Plot seismograms in SAC format | |
| Compute Peak Ground Acceleration/Velocity and Intensity | |
| Convert topographic slope to Vs30 velocities | 
spotter
| Generate forward and backward flowlines and hotspot tracks | |
| Evaluate a plate motion model at given locations | |
| Evaluate a plate motion model on a geographic grid | |
| Finite rotation reconstruction of geographic grid | |
| Create CVA grid from a gravity or topography grid | |
| Create CVA grid from seamount locations | |
| Associate seamounts with nearest hotspot point sources | |
| Find stage poles given fracture zones and abyssal hills | |
| Manipulate total reconstruction and stage rotations | |
| Get mean rotations and covariance matrices from set of finite rotations | 
windbarbs
| Plot wind barbs in 2-D and 3-D | |
| Plot wind barb field from two component grids | 
x2sys
| Create bin index listing from track data files | |
| Calculate crossovers between track data files | |
| Extract content of track data files | |
| Get track listing from track index database | |
| Initialize a new x2sys track database | |
| Extract subset from crossover data base | |
| Merge an updated COEs table (smaller) into the main table (bigger) | |
| Update track index database from track bin file | |
| Report statistics from crossover data base | |
| Determine least-squares systematic correction from crossovers |